I'm a long time member of JBO but can't remember what email i registered it to.

Anyway, my gf's sunfire is having severe hessitation problems while accelerating. While cold it's all the time, after about 5 miles it's during med/hard acceleration, and 10-15 miles it's only during hard acceleration. In park or nuetral it revs just fine, and i haven't tried reverse while cold. Only in drive have i/her come across this. 3 days ago she told me about it (been going on for weeks) and i drove the car then with no problems. That day it was dry out, today i drove it to work, it'd been a bit rainy, and dew on the windows when i got off work, and it was very noticeable. It cuts out really bad.

Any ideas what my problem could be?

check the hose on the map sensor.. may be dried out. if its a 2,4

i can't go out and see now but it's a 99 sunfire se coupe, pretty sure it's a 2.2l 2200 I4

time for another shot in the dark... i would think that given when the problem arises, its an ignition issue.. coil, wires... maybe even worn plugs?

that's what i had originally thought when she told me about the problems, but since it doesn't do it while in nuetral or park i was unsure.

because there is no load on the motor in park or neutral.. or very little... could even be the alternator dying, most part stores can check it for free..
again.. its more a educated guess.. things like hesitation can be caused by any number of things.. But thats where i would start looking if it were me..

and the hose to the MAP sensor would act up at idle, not higher RPM.. its a vacuum line... just had to replace mine actually.. lol

ok thank you i'll start there then