Questionhello. i have a 2003 chevrolet extreme pick up truck with 4.3 v-6, 36,000 miles. i bought it new and maintain it correctly. the check engine light came on about 8 months ago and i had a friend put his computer on it and he said all 3 oxygen sensors are bad. since they are so expensive and the truck has been running perfectly, i have not changed them yet.
well, last night after the truck had set for about 7 hours, and it was a little chilly out, about 45 degrees, on initial start up it was running rough, like on only 4 cylinders, and had a smell coming from the muffler and it had a knocking sound coming from the engine, like a rod knock, but had normal oil pressure. i immediatly shut it off. then tried starting it again, and still running rough and knocking, so i shut it off again. tried it one more time, and then it ran smooth and no knocking sound.
also, while it was knocking, i noticed that the check engine light was blinking, which it has never done before.
well, i let it run for about 5 minuts and warm up, then drove it home 2 miles from my friends house, and it ran peerfectly.
started it this morning and it is running and sounding normal.
it is a stock engine with only an AIRRADE air cleaner system on it. stock exhaust.
any suggestions ? my friend said it might me the MAF sensor going bad, but i dont know exactly what the MAF sensor does.
i have an extended warranty on the truck, but if it is something not too expensive i would just rather repair it myself and save having to take it to the dealer and get a rental car.
thank you very much in advance.....leonard.
AnswerIf you have the warranty, but start messing with it, but are unable to correct the problem, you might create a problem with the warranty. I'd probably want them to check it.
One thing you might check, is make sure the ground strap from the engine to the firewall is intact.
Van
