I got a 92 S10 Blazer 4.3L V6 TBI. When i start it up after it has been sitting for at least more then 10 minutes, it will "lope" or you could say it idles erraticallyfor about 5-10 seconds before it smooths out to a normal idle. If i give it gas withen this 5-10 seconds, it will idle to normal in about half the time. While it idles erratically, the service engine light comes on but goes off shortly after the idle smooths out. I put a K&N filter on,replaced the fuel filter,added this prolong fuel injection cleaner,put on new plugs,wires,distributer,rotor/cap............and nothing has changed! The manual gives quite a few things that could be wrong and most of them are quite expensive or time consueming(exa.timming chain,leaking head gasket,etc.....). I took it in to a mechanic and told him the problem because of coarse it would'nt do it for me when i showed him and he said that the Carb(TBI) needed to be rebuilt......which he said would be close to $400. Any ideas anyone? Is the mechanic right? Thanks for the help guys..........

on the carb there is a sensor/solenoid that richens up the mixture for cold start purposes. its been a while since i have worked on a tbi engine so i cant remember where it is at but look for a sensor or a solenoid ( its not the fuel injector solenoid/s) on the carb. also check your fuel pressure and your fuel pressure regulator. also scan the computer and find out what the code is.

He said the check engine light came on which means he can get a code.

Do the paperclip trick and get your check engine code and we can go from there.

Do anything else is a waste of time when the code will tell you what is wrong.

Sounds to me like a leaking injector. Clue Ten min sit time??? Injector leaking fuel so the cylinders are geting fuel fouled and the lope is because of that. 1 good rev and the fuel is cleared out. so it returns to a good idle. The mil light I would bet is a o-2 code for a rich mixture.
To check this run the truck for about 5 to 10 mins then turn of the engine and look at the throttle body injectors and look for a leak. I bet you will find 1. Or if you dont have time to sit there and watch for a leak put a piece of paper under the injectors and recheck it in 30 mins and see if the paper is wet BUT PLEASE REMEMBER TO REMOVE THE PAPER BEFORE YOU RESTART THE ENGINE.
Fireplug

Thanks for the help guys. I had a diognostic done and they said it was the EGR selinoid/sensor and the EGR valve. Replaced both, which was close to $200, and now it runs like a champ..........thanks :smile: