Pontiac Repair: 2001 Pontiac Montana/3.4 engine, crank case, pontiac montana

Question
First of all season's greetings. Now to the bad part. I have a vehicle in my shop that I replaced the lower intake gaskets and the MAF. These problems wereverified by a local GM dealer prior to repairs. The gaskets were rotted at hte rear of the engine. The MAf problem was confirmed by using a TECH 2 at the dealer now I have a fast idle problem about 2000 rpm with the engine cutting back at 4000 rpm I suspect a vacuum leak but I cannot find it by using an areosel method(choke cleaner). Any help would be certainly appreciated. Thanks Balaine.

Answer
Hey Blaine:

Happy holidays to you as well. Was the the original problem or did this crop up after the intake gasket replacement? If it cropped up after I would suspect that maybe the gaskets were not seated properly on the head and it's sucking the air in from the crank case? to check that pull out the pcv valve and plu that and also pull out the breather pipe from the snorkel and spary carb cleaner into the crank case and see what happens. You may have an injector o-ring leaking where they go into the lower intake.. was the MAF the correct one for the van and is in installed with the air flow going the correct way maning it's not in backwards.... Unplug the MAF and see if that makes a difference it will stumble and hesitate but will run none the less. Also you may want to do a memory dump on this disconnect the (+) cable and tounc it to the (-) for about a minute and then reconnect it then turn the key on and then back off again wait 30 seconds and do it again before you start it so the ecm will learn the IAC position. Latsly you didn't mantion if it actually ran okay without a miss I have seen the push rods get switched on this and it casue all kinds of issues the exhaust pushrods are the longer ones. If that were an issue it would run like crap and have a faster than normal idle.. Just a few things to check good luck :)