Alright other folks with my same problem i have a 97 silverado with a 5.7l 350 vortec and the same thing is happening to me. it just started to get snowy and cold and so when it started with me i assumed it was just bad gas i added water remover and changed the fuel filter and nothing. I sifened about 5 gallons of gas into my buddys car after he ran out and no problems for him. i tapped the cats with a hammer and they sound clear then gave it a little rev and barley any gunk came out of my exhaust but hopefull tomorrow i will get it to the shop the mechanic i use is one of the guys who treats your trucks better then his. but when i get it in ill let you know whats throwing mine off. also my girlfriends dad is a mechanic and worked for a company that only drove 90's chevs and he said to check the 02 sensor says it might be the problem i dont know how but just a thought

 

You guys may want me hanged for heresy but someone has to say it - when all else fails, it may be time to head to the dreaded ... DEALER!

I once completely rebuilt an Oldsmobile motor. It ran rough and I couldn't find the problem; okay, I didn't run a cylinder pressure check. I took the car to a local dealer and the mechanic found the problem very quickly - one of the new GM valve lifters that I purchased from the dealership was too high! The lesson I learned was that, sometimes, the dealer knows best and that may be why they charge so much! Although, in the Phoenix area, the independent shops charge almost the same hourly rate as the dealerships.

Good luck!

 

Check for a bad ground. I replaced a thermostat once, and did not hook up a ground by the thermostat housing. It took me a long time, and lots of parts later before I found the problem (self inflicted). good luck.

 

I have the same issue with a 88 K1500 5.7l. I've replaced the fuel pump, fuel pump relay, fuel pressure regulator, fuel injectors, fuel filter, egr valve, egr solenoid, did a complete tune up, replaced the map sensor, tps sensor, ignition coil, ignition control module, idle air control valve, and it's still no better then when I started. Any other suggestions?

 

Hello, Sorry for not responding, Been busy. The problem I had with the peroidic missing or rough running at idle sounds diferent than your problem but who knows, could be a different reaction to the same thing. My problem reared its head when I had Chevrolet replace the motor with a New out of crate GM engine, same engine but new. The original engine had a bad cyliner and it would have cost more to rebuild then replace. I have the old engine in my garage in the crate the new one came in.

My miss is only in nutral or park when the engine is free idling. It disappears when a load is on it like turning on the AC even in free idle, or putting it in gear etc... Chevrolet looked it over several times and can't figure it out. Even put a new computer in and that did not change the problem. (They put the old computer back and did not charge me.) I now have about 75K on this engine and the problem seems to have calmed down. The issue I still have is that if I use the AC, then turn off the engine for at least 15 minutes, it will start then stall immediately, then struggle to start. Even with Fuel Injection I have to hold down the pedal and then it will start. Once it starts I have to race it at low RPM until it clears it's head then it will run perfect. That problem has been there since it was new in 1994 and no one could find out why it does that. Even with the new engine it still has that problem.

I hope you find out what your issue is. I love my Blazer. It still looks new and I get compliments all the time. The original miles on the entire vehicle currently is 318,000 + and no other mechanics have had issues other than the engine at 249,000 and the tranny before that at 214,000. This vehicle simply drives so nice and stable. that is why I have kept it.

 

I have experienced similar problems and it was usually the coil. More output is needed when accelerating or under load and this is worth a try.

My Chevy Tahoe had problems of lack of power that seemed like the mixture was too rich. Went to 4 different Chevy dealers and 4 different independent garages and $1500 later I still had the problem. Over time the problem got worse until it became obvious that the problem was a bad intake manifold gasket that was letting coolant into the cylinders. Luckily it was caught before it destroyed the engine bearings. Found later that bad intake manifold gaskets are a very common problem with GM engines in trucks and in cars.

 

anyone can tell me where the cam sensor is located on the mark 3 chevrolet 1500 5.7 van
is it in the distributor or on the camshaft

 

rough idling smoke wjhen accelerated stalling pressure regulator bad

 

hi i'm new to this. i have a 96 chevy 1500 with a 5.7, the other day it started right up i went and shut it off and it would restart. it kept acting like the timing chain jumped, we poured a little gas down the intake but nothing but back firing did have a small fire in the intake. any way we found that i had a bad cap and rotor replaced both and started right up but now it misses and floods out also replaced plus and wires please help

 

make shure your fuel pressure is rock solid at 12 to 15 psi if it falls off a touch fuel pump bad you also need to make shure you have good fuel volume