The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 1991 GMC runs poorly after engine is warm

willymakeit · 12-25-2006, 02:57 PM

Thanks for the replies everyone. I remembered that I didn't clear the codes after replacing the IAC ..... so I did that and have drove the PU a couple of times and both times it went about 3 miles before showing symptoms again....... this time without the engine light coming on.

I have to admit that I never would have thought of the temp sensor. As far as a smell goes, I did notice a strange smell after replacing the IAC but it didn't really smell quite like rotten eggs but it did have a sort of acrid odor.

As far as the O2 sensor goes, I can safely say that it is not in the exhaust before the converter (exhaust had been totally replaced and converter was left out ...... as well as the air pump). Also checked around the exhaust manifold on both sides and failed to locate it at either location although I haven't been able to fully access the passenger side fully yet.

Hopefully I'll have more time to check things out a little more tomorrow.

I truely appreciate everyones input!

12-25-2006, 02:57 PM	#9
willymakeit Registered User Join Date: Dec 2006 Location: kansas Posts: 7	Re: 1991 GMC runs poorly after engine is warm Thanks for the replies everyone. I remembered that I didn't clear the codes after replacing the IAC ..... so I did that and have drove the PU a couple of times and both times it went about 3 miles before showing symptoms again....... this time without the engine light coming on. I have to admit that I never would have thought of the temp sensor. As far as a smell goes, I did notice a strange smell after replacing the IAC but it didn't really smell quite like rotten eggs but it did have a sort of acrid odor. As far as the O2 sensor goes, I can safely say that it is not in the exhaust before the converter (exhaust had been totally replaced and converter was left out ...... as well as the air pump). Also checked around the exhaust manifold on both sides and failed to locate it at either location although I haven't been able to fully access the passenger side fully yet. Hopefully I'll have more time to check things out a little more tomorrow. I truely appreciate everyones input!