dartlord2001

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

gvandude

Hello John,
I have the exact same problem w/ my 95 G20 van w/ 5.7 TBI. I just purchased the van. I tuned it up. Still lugs. Have you fixed the problem yet? Anyone else with this problem? Solutions?
Thanks

kcb37

It may be a knock sensor. I don't know for sure, but I know a bad one will make it run rough.

re_boot1

Hello,
I have a 1997 Silverado K2500 4x4 with the Vortec 454 5 speed standard having the same problem. I've replaced the plugs, wires, cap, rotor and knock sensors with no improvement. It'll smoke the tires thru 4th till it warms up then gets a dead miss and will hardly move out of it's own way. Anyone with any idea's would be greatly appreciated.

kcb37

It could be the timing not adjusting after intial warm up. I don't know what would do that though. You may want to call a good shop and ask for suggestions. If it has happened to 3 of you undoubtedly in diferent areas that almost has to rule out bad gas. You might also ask if cam sensor going out could cause this and have the computer not firing the cylinders at the right time. I'm sorry but I am just as lost as all of you on this one.

re_boot1

I have heard of the cam sensor causing this on other trucks. I'm putting the truck on a diagnostic computer Sat morning for a full workup. I'll post what I find when I get home. By the way, I'm in North Texas and gas quality is fairly good around here.

kcb37

A cam sensor seems to be about the only other thing I can think of. If it dosen't cost to much and it isn't hard to get to you may want to replace it anyway.
Let us know what you find out re_boot1

re_boot1

OK, ran a full diagnostic on the truck. narrowed it down to the in-tank feul pump. The computer reads that all of the electronic components of the pump are running at optimal, but a pressure guage connected to the feul rail on the intake showed the pressure was 58psi at an idle and it dropped to 45@ 2000 rpms. 58psi is minimal for a big block, 60 is optimal. The book shows the small block should be around 50 to 55 psi for optimal pressure. The drop in feul pressure causes the engine to lean out under a load such as accelerating and pulling and could cause the engine to burn a piston from the increased cyllinder temp. The pump for mine is $150 at the dealership and it's easier to lift the bed and slide it back than to drop the tank. Hope this helps.

yekots

Guys I have been chasing this exact same problem and finally cured mine but not saying it will cure your problem. I have a 98 GMC K1500. I replaced the plugs with OEM AC Delcos and that did not fix it. I replaced the cap and rotor with OEM AC Delco and that did not fix it but that did need to be done, a lot of build up on the points. I then went in and replaced the coil and plug wires with MSD parts and that finally seemed to fix the stalling problem. Now the truck seems to run better than it ever has.

One other thing that I did that may have helped. When I replaced the coil there is a little electronic box with a heat sink on it mounted to the same bracket as the coil(sorry, I forgot what this part was called). I removed this and the heat sink from the bracket, cleaned it up because it looked as though it had heat sink compound on it, the same compound that I use on my home computer CPU heat sink. I put a new layer of compound on it and then remounted it.

Now one or all of these things might have fixed it but not sure which one but I have driven over 1000 miles and still works great.

Good Luck!

dartlord2001

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.