I have a 2000 Silverado 1500 with a 4.3 engine, standard 5 speed 2 wheel drive. I have an occasional misfire when cold and on exceleration. It will also misfire when driving occasionally. I have replaced plugs, plug wires, distributor cap and rotor, sensor in distributor and coil. Starts and idles great. Not sure where to go next. Took it to a local mechanic he suggested it my be a sticking injector. Shows no codes. Thanks for any help.

 

I'd try using some Techron Complete down the fuel tank, then take it out somewhere safe like a wide country road, where there are no police and rev that motor up, Italian-Style. I also think your fuel injectors are dirty, and this Techron will clean them out after all the parts you have put in your Chevrolet. Not to push a brand but some people like Seafoam instead.

I've run Chevron or Texaco gasoline with Techron, since fuel injection came out in the mid-1980's and have never had any fuel injector problems at all over all of those years. That pretty much speaks for itself,or I am just one lucky man.

 

Thanks for the advice! This mechanic said to use transmission fluid down the intake and let it stand over night. Did that and it seemed to help some but never cleared. I have some Seafoam that I haven't tried yet. We don't have a Texaco or Chevron station near by, I'm in a small town in northern Arkansas. Moved here to retire from Calif. I will certainly try the Seafoam. It seems to run great except for the occasional hiccough after it warms up. Thanks for the advice. Will let you know how it works, not today it's too cold!

 

I'm not so sure that automatic transmission fluid would work going down your intake, but it's possible. People used to run a quart of it down into the engine oil to clean out sludge, so I suppose it's possible. Please let us know if this works.

 

Hi, Put Seafoam in (2 0z, per gal. approx.) and punched it down the road. Now have an error code P0300 which is a misfire. I may try to replace the crank position sensor which it shows may be a problem. Don't think it is expensive. May drive it a little with the Seafoam in it and see if it clears first. It wasn't showing the code before but I really hadn't punched it. Saw a suggestion that there may be play in the distributor but it didn't feel loose. Another said it could be an intake gasket but I would rather not go there yet, runs steady at idle. Will keep trying but may be a slow process. Thanks again!

 

Seafoam has helped. I cleared the codes and will fill it with gas. May add 1 oz. per gal. and drive it for awhile and see if code reappears. Definite help on exceleration. Still have a rare miss or bump while driving. Will let you know. Don't think the crank position sensor would have anything to do with it. Will let you know. Thanks!