Rough idle and low power

Asked by Feb 16, 2017 at 01:31 AM about the 2005 Chevrolet Silverado 1500 Work Truck Short Bed 2WD

Question type: Maintenance & Repair

I have a 05 chevy silverado with the 4.3 v6. After
about a minute after starting it, it begins running
really rough and rich like a cylinder isnt firing. When
driving, it has extremly low power until i hit around
45 mph, then it feels like the cylinder begins firing
again and everything goes back to normal. Had an
exhaust leak when the problem started, but fixed it
shortly after. Have also changed plugs, wires,
distributor cap and rotary cap. Next step is to
change fuel filter.

9 Answers


Sounds like a spark plug is faulty or a lead. Fuel injector might need replacing ?


you can remove the idle air control (IAC) and clean that area up , even spray some carb cleaner down the trottle , try some methanol based dry gas , intermediate problems are the worst .


let us know if problem is resolved

Pulled iac and cleaned it, still has the problem. Not sure if theres a way to check if its faulty, but the engine doesnt have the rpm problems normally indicative of a bad iac. Im assuming that if the fuel pump was going out, the problem would persist no matter what speed im going. Could it be a clogged injector? Or maybe the mass air flow sensor?


From my experience fuel pumps will have one last go then when you start it next time they're done for .Fuel filter is rarely the problem , If you have the equipment and expertise you can test each sensor and actuator ,have you scanned for codes even though the C.E.L. isn't on ?How do the plugs look ? you might want to bring it to a technician and they can scan it real time . You'll need to find a good , honest one . Some will just replace things like a curb side mechanic .Sad but true there's a lot more ego than talent out there . Like I said intermediate problems are the worst .


E.G.R valve ? A haynes manual will say how to test most of the components .

Yeah, all of my knowledge is more mechanical than technical. Used to have a 91 model of the same truck, so i learned to take it apart and put it back together, but most of the electrical and sensor components are still new to me

Plugs are brand new, first thing i changed once this all started

So, somewhat strange update. Figured that since i was at a loss, i might as well pull and clean the egr valve. Looked it up in chiltons, and haynes, but their images of the egr location is wrong. From the image i can see what it looks like, and i cant find anything similar looking on the block. . . . did this model truck not come with an egr installed, or am i just missing something i dont know about?

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