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5.7L Engine Miss. Very Frustrated! Tried Everything.
CF Beginner
Joined: Jan 2020
Posts: 1
Likes: 0
Hello,I am a new member.I have a '94 4x4 silverado 1500.I am having a problem with a miss in the engine.I had a mechanic that works for a GM dealership to look at it.He scanned it and his scanner found no problems with it.It idles fine but when you give it a little throttle,it starts to miss and tries to stall.Its like it loses ignition totally or fuel flow.He unhooked the hose from the egr solenoid and it would run smoothly when giving it throttle but would still cut out and miss while driving it.I replaced the solenoid and that did not fix the problem.He also noticed the fuel pressure regulator was leaking so i replaced that too but it did not fix the problem.The fuel pump,fuel filter,and distributor were all replaced about 15 months ago as well as the coil and it ran fine until about 2 months ago then it started having the miss gradually.I have tried different plug wires ,new rotor and dist. cap and new plugs and nothing seems to help.The engine starts getting the miss after it warms up when sitting still and misses at all times when driving.The engine is a 5.7L with TBI.Any help with this would be greatly appreciated as i have tried everything i can think of.
Thank You,
John
Thank You,
John
CF Beginner
Joined: Jan 2020
Posts: 1
Likes: 0
Hello,I am a new member.I have a '94 4x4 silverado 1500.I am having a problem with a miss in the engine.I had a mechanic that works for a GM dealership to look at it.He scanned it and his scanner found no problems with it.It idles fine but when you give it a little throttle,it starts to miss and tries to stall.Its like it loses ignition totally or fuel flow.He unhooked the hose from the egr solenoid and it would run smoothly when giving it throttle but would still cut out and miss while driving it.I replaced the solenoid and that did not fix the problem.He also noticed the fuel pressure regulator was leaking so i replaced that too but it did not fix the problem.The fuel pump,fuel filter,and distributor were all replaced about 15 months ago as well as the coil and it ran fine until about 2 months ago then it started having the miss gradually.I have tried different plug wires ,new rotor and dist. cap and new plugs and nothing seems to help.The engine starts getting the miss after it warms up when sitting still and misses at all times when driving.The engine is a 5.7L with TBI.Any help with this would be greatly appreciated as i have tried everything i can think of.
Thank You,
John
Thank You,
John
Keith
I'm here for the party
Joined: Feb 2019
Posts: 1,467
Likes: 83
From: Maryland
whoever reads this post keep in mind some people have mentioned a couple different fuel injection setups not knowing what year the post they responded to. just a FYI pre-95 trucks should have a tbi unit (no spider injection) and 96+ should have the spider injection. similar sensors but different types of injection. heres a write-up about the sensors for tbi units
Troubleshooting sensors and how to test
the sensors for other engines should work the same but the readings might be a tad off
Troubleshooting sensors and how to test
the sensors for other engines should work the same but the readings might be a tad off
CF Beginner
Joined: Nov 2020
Posts: 1
Likes: 0
Power, Spark, Fuel, Air, Cooling
If you are driving a 1994 Chevy, the chances are there are some electronic problems with it, and the way the engines operate off of the different emissions controls can suffer greatly if one or more of those parts aren't working. Take a look at the electrical circuit and make sure you have good grounds on everything. An easy way to check is by taking a Test Light and jumping from the black ground wire of the (or whichever) component to the negative terminal on the battery. If the light comes on it's a good ground. If not it needs to be connected, clean metal to clean metal.
Another issue I have had with fuel delivery in these era trucks/engines is the fuel pump relay. I replaced my entire fuel system and it ended up I changed the wrong relay (since they use the same in multiple spots sometimes).
If you think you are having trouble with a particular part, such as the ECM, try to find the ground for it and make sure it's good.
V/r,
Toe Face
Another issue I have had with fuel delivery in these era trucks/engines is the fuel pump relay. I replaced my entire fuel system and it ended up I changed the wrong relay (since they use the same in multiple spots sometimes).
If you think you are having trouble with a particular part, such as the ECM, try to find the ground for it and make sure it's good.
V/r,
Toe Face
Hey,
I Am The One That Posted The Orig. Message.Since Then I Have Replaced The EGR Valve itself And that seems to have fixed the problem with it idling smoothly but cutting out when you rev it up.But it still runs rough when you drive it.Rough When you start going but as you gain rpm it runs smooth thenwhen you are at speed and the rpm drops back down you can feel it jerking like it is cutting out.I also replaced the timing chain which it did need but it did not fix the problem.I Had a guy check it with OBD I Scanner and he cannot find anything wrong with it.Since April I have replaced:EGR valve,EGR valve Solenoid,dist. cap,rotor.,plugs,plug wires,fuel pressure regulator,MAP sensor,Alternator,and timing chain.I have even redone the engine from the heads up with new head gaskets and all related gaskets from there up and adjusted the valves 2 or 3 times but i am still having problems.Within the last 2 years I have replaced the Fuel pump,distributor,and throttle pos. sensor and probably more stuff i cant even think of.where mine is a '94 i dont think it has a knock sensor,camshaft pos. sensor,or crankshaft pos. sensor and everything changed for '96 and after.well, I Thought I'd Give Y'all an update
P.S. The guy that checked it with the scanner said maybe it could be the computer (ECM) but i dont want to pay $100.00 and that not fix the problem.Hopefully I Didnt cause a vacuum leak after i put it back together after doing the head gaskets.
I Am The One That Posted The Orig. Message.Since Then I Have Replaced The EGR Valve itself And that seems to have fixed the problem with it idling smoothly but cutting out when you rev it up.But it still runs rough when you drive it.Rough When you start going but as you gain rpm it runs smooth thenwhen you are at speed and the rpm drops back down you can feel it jerking like it is cutting out.I also replaced the timing chain which it did need but it did not fix the problem.I Had a guy check it with OBD I Scanner and he cannot find anything wrong with it.Since April I have replaced:EGR valve,EGR valve Solenoid,dist. cap,rotor.,plugs,plug wires,fuel pressure regulator,MAP sensor,Alternator,and timing chain.I have even redone the engine from the heads up with new head gaskets and all related gaskets from there up and adjusted the valves 2 or 3 times but i am still having problems.Within the last 2 years I have replaced the Fuel pump,distributor,and throttle pos. sensor and probably more stuff i cant even think of.where mine is a '94 i dont think it has a knock sensor,camshaft pos. sensor,or crankshaft pos. sensor and everything changed for '96 and after.well, I Thought I'd Give Y'all an update
P.S. The guy that checked it with the scanner said maybe it could be the computer (ECM) but i dont want to pay $100.00 and that not fix the problem.Hopefully I Didnt cause a vacuum leak after i put it back together after doing the head gaskets.
CF Beginner
Joined: Feb 2021
Posts: 1
Likes: 0
Wow you people love to throw parts at cars. I know it's hard to put them in the shop but if you honestly don't know how to diagnose the car then don't waist your money. Now you have thrown all this money into which probly most of the parts probly didn't even need to be changed and then you might even have to put it into the shop. Just doesn't seem very smart to me.
For the guy who started the thread have you even checked for vacume leak yet? Easy way is to take a spray bottle full of water and spray down the vacume lines and listen for the motor to change rpm some.
I would also check the fuel injector to see if they are spraying good. Take off the breather and hook up a timing light to one of the spark plugs and aim the light at the throttle body. You should be able to see spray the fuel injectors are putting. You should look like a mist and be very consitant and uniform. I would suggest this also to the guy above with the 89.
For the guy who started the thread have you even checked for vacume leak yet? Easy way is to take a spray bottle full of water and spray down the vacume lines and listen for the motor to change rpm some.
I would also check the fuel injector to see if they are spraying good. Take off the breather and hook up a timing light to one of the spark plugs and aim the light at the throttle body. You should be able to see spray the fuel injectors are putting. You should look like a mist and be very consitant and uniform. I would suggest this also to the guy above with the 89.
CF Beginner
Joined: Apr 2021
Posts: 1
Likes: 0
Hey,
I Am The One That Posted The Orig. Message.Since Then I Have Replaced The EGR Valve itself And that seems to have fixed the problem with it idling smoothly but cutting out when you rev it up.But it still runs rough when you drive it.Rough When you start going but as you gain rpm it runs smooth thenwhen you are at speed and the rpm drops back down you can feel it jerking like it is cutting out.I also replaced the timing chain which it did need but it did not fix the problem.I Had a guy check it with OBD I Scanner and he cannot find anything wrong with it.Since April I have replaced:EGR valve,EGR valve Solenoid,dist. cap,rotor.,plugs,plug wires,fuel pressure regulator,MAP sensor,Alternator,and timing chain.I have even redone the engine from the heads up with new head gaskets and all related gaskets from there up and adjusted the valves 2 or 3 times but i am still having problems.Within the last 2 years I have replaced the Fuel pump,distributor,and throttle pos. sensor and probably more stuff i cant even think of.where mine is a '94 i dont think it has a knock sensor,camshaft pos. sensor,or crankshaft pos. sensor and everything changed for '96 and after.well, I Thought I'd Give Y'all an update
P.S. The guy that checked it with the scanner said maybe it could be the computer (ECM) but i dont want to pay $100.00 and that not fix the problem.Hopefully I Didnt cause a vacuum leak after i put it back together after doing the head gaskets.
I Am The One That Posted The Orig. Message.Since Then I Have Replaced The EGR Valve itself And that seems to have fixed the problem with it idling smoothly but cutting out when you rev it up.But it still runs rough when you drive it.Rough When you start going but as you gain rpm it runs smooth thenwhen you are at speed and the rpm drops back down you can feel it jerking like it is cutting out.I also replaced the timing chain which it did need but it did not fix the problem.I Had a guy check it with OBD I Scanner and he cannot find anything wrong with it.Since April I have replaced:EGR valve,EGR valve Solenoid,dist. cap,rotor.,plugs,plug wires,fuel pressure regulator,MAP sensor,Alternator,and timing chain.I have even redone the engine from the heads up with new head gaskets and all related gaskets from there up and adjusted the valves 2 or 3 times but i am still having problems.Within the last 2 years I have replaced the Fuel pump,distributor,and throttle pos. sensor and probably more stuff i cant even think of.where mine is a '94 i dont think it has a knock sensor,camshaft pos. sensor,or crankshaft pos. sensor and everything changed for '96 and after.well, I Thought I'd Give Y'all an update
P.S. The guy that checked it with the scanner said maybe it could be the computer (ECM) but i dont want to pay $100.00 and that not fix the problem.Hopefully I Didnt cause a vacuum leak after i put it back together after doing the head gaskets.
Exact issues. This is what corrected my issues. He
CF Beginner
Joined: Mar 2022
Posts: 1
Likes: 0
Hey,
I Am The One That Posted The Orig. Message.Since Then I Have Replaced The EGR Valve itself And that seems to have fixed the problem with it idling smoothly but cutting out when you rev it up.But it still runs rough when you drive it.Rough When you start going but as you gain rpm it runs smooth thenwhen you are at speed and the rpm drops back down you can feel it jerking like it is cutting out.I also replaced the timing chain which it did need but it did not fix the problem.I Had a guy check it with OBD I Scanner and he cannot find anything wrong with it.Since April I have replaced:EGR valve,EGR valve Solenoid,dist. cap,rotor.,plugs,plug wires,fuel pressure regulator,MAP sensor,Alternator,and timing chain.I have even redone the engine from the heads up with new head gaskets and all related gaskets from there up and adjusted the valves 2 or 3 times but i am still having problems.Within the last 2 years I have replaced the Fuel pump,distributor,and throttle pos. sensor and probably more stuff i cant even think of.where mine is a '94 i dont think it has a knock sensor,camshaft pos. sensor,or crankshaft pos. sensor and everything changed for '96 and after.well, I Thought I'd Give Y'all an update
P.S. The guy that checked it with the scanner said maybe it could be the computer (ECM) but i dont want to pay $100.00 and that not fix the problem.Hopefully I Didnt cause a vacuum leak after i put it back together after doing the head gaskets.
I Am The One That Posted The Orig. Message.Since Then I Have Replaced The EGR Valve itself And that seems to have fixed the problem with it idling smoothly but cutting out when you rev it up.But it still runs rough when you drive it.Rough When you start going but as you gain rpm it runs smooth thenwhen you are at speed and the rpm drops back down you can feel it jerking like it is cutting out.I also replaced the timing chain which it did need but it did not fix the problem.I Had a guy check it with OBD I Scanner and he cannot find anything wrong with it.Since April I have replaced:EGR valve,EGR valve Solenoid,dist. cap,rotor.,plugs,plug wires,fuel pressure regulator,MAP sensor,Alternator,and timing chain.I have even redone the engine from the heads up with new head gaskets and all related gaskets from there up and adjusted the valves 2 or 3 times but i am still having problems.Within the last 2 years I have replaced the Fuel pump,distributor,and throttle pos. sensor and probably more stuff i cant even think of.where mine is a '94 i dont think it has a knock sensor,camshaft pos. sensor,or crankshaft pos. sensor and everything changed for '96 and after.well, I Thought I'd Give Y'all an update
P.S. The guy that checked it with the scanner said maybe it could be the computer (ECM) but i dont want to pay $100.00 and that not fix the problem.Hopefully I Didnt cause a vacuum leak after i put it back together after doing the head gaskets.
Last edited by Erok101; Mar 22, 2022 at 4:38 PM.
CF Beginner
Joined: Jan 2023
Posts: 1
Likes: 0
Knock knock who's there.
well, i finally called a shop, and im going in tomorrow morning. he said more thank likely, its something very minor and he would have to drive it to tell. i hope all goes well. he also said if it happens more when your going up hill, its probably your spark plug wires...this might be my case...ZT.
When I was chasing down the same issues with my 92 5.7 chev. I went back to what I was taught. In the black of night I started my truck popped the hood and gave a close inspection off the plug wires. Sure enough I found one of the boots to the plug was arching off under the boot to the heat shield. Couldn't see this in the light but found the faulty boot under the cover of darkness. May want to take a look and see if your boot is bad.
CF Beginner
Joined: Jan 2024
Posts: 1
Likes: 0
New plug wires?
Hey
This is the one that posted the orig. thread. as I said before,I had a guy check my truck with a scanner and he found no problems.I found an advance auto parts with an OBD I scanner.They checked it and their scanner showed a code 42.The printout says Ign System problem-Elec spark timing circuit fault.They said a knock sensor could cause this but they didnt know that for sure.My Haynes manual says knock sensor problem would be code 43.I have tried to locate the elec spark control on the motor but I cant find it.The Haynes manual shows it right by the TBI on the right side but its not there on mine.I cant find the 4 wire plug for it either.Is anyone familiar with this?The truck is a '94 W/5.7L
Thanks
This is the one that posted the orig. thread. as I said before,I had a guy check my truck with a scanner and he found no problems.I found an advance auto parts with an OBD I scanner.They checked it and their scanner showed a code 42.The printout says Ign System problem-Elec spark timing circuit fault.They said a knock sensor could cause this but they didnt know that for sure.My Haynes manual says knock sensor problem would be code 43.I have tried to locate the elec spark control on the motor but I cant find it.The Haynes manual shows it right by the TBI on the right side but its not there on mine.I cant find the 4 wire plug for it either.Is anyone familiar with this?The truck is a '94 W/5.7L
Thanks
Last edited by Chvy guy; Jan 1, 2024 at 5:32 PM.