okay... what is the correct idle for both a 3.4 and 3.8 supposed to be. my 3.4 runs at 900 to 1000rpm while gf's 3.8 runs somewhere around 1000 and over.....i haven't found any data out there that explicitly tells what the correct idle speed is supposed to be... thnx in advance

 

idle depends on what the computer wants it to. If you have access to a scanner with datastreem plug it in and look at the desiered idle speed and if its what the computer whats then its correct. But 1000 rmp is kind of high. Not sure if the computer is compensating for something that is broke or worn out or not getting the proper signal form something. Is that ater the engine had warmed up or is that right after you start it up in the morning. Cus during start up the engine will idle somewhat higher than normal and drop down to around 600-800 rpm after the engine has warmed up and gone into closed loop.

 

nope, don't have a scanner, yet...but i'm just really curious that 2 motors of different displacements would behave identically. the 3.4 is out of a 95 while the 3.8 is from a 99. this means that they also have 2 different PCMs. Maybe they need to have the TBs cleaned or IACs swapped out.

 

you might wanna try and fuel injection cleaning, throttle body cleaning, and iac cleaning and see if that helps any.