Pontiac Repair: my 2000 pontiac grand prix se, torque converter clutch, mass air flow sensor

Question
Hi
I recentlly bought my 2000 pontiac grand prix and it runs great except it has a intermitant stutter. upon accceration at about 1600 rpms. we took it to a shop ang they said that the egr valve is causing the car to go into open loop to soon. if we unhook the egr valve the car won't do that at all. we replaced the valve but the car still does the same thing. Any advise?

Answer
Hi Daisy:

First off the egr valve doesn't have anything to do with going into "closed" loop. My guess is that this engine has either a tcc chuggle issue or a lean misfire. the chuggle issue when the car is doing it and it's in 4'th gear and maybe about 45 MPH and it's doing it try this. keep your foot on the gas and just tap the brake pedal and see it it does away. If so it can be an issue withe the tcc which is the torque converter clutch in the transmission. Or this the engine has a slight lean misfire and when the tcc is applied you feel that misfire due to the fact that when the tcc is applied there is no slip between the engine and transmission. without the tcc on the slip between the engine and transmission covers up the misfire. Now what can be causing the lean miss?? An dirty injector, a mass air flow sensor, low fuel pressure... The reason you feel it worse withe the egr hooked up is the engine is already running lean enough to cause a lean miss and when the egr is applied it leans it out even more that is why your feel it more. I would look at the fuel trim #'s with a scan tool when the car is doing it it will give you a better idea as to what is going on. good luck :}