97 Chevy Lumina sedan, 131000mi, normally runs fine but sometimes between 50-70 mph, after I take my foot of gas to maintain speed and then barely put it back to keep even speed it starts to surge just a bit but noticeably, and if I rev it a bit it will go away but it is getting a bit more pronounced and I have aroad trip coming up. Put new fuel pump in a year ago after similar issue, b/c mechanic said pressure was too low.
Sounds like a torque converter in the trans going in and out. Get it checked to confirm but I would not consider a long trip till you are sure.
October, 16, 2011 AT 2:11 AM
It could be a few things. ASE mentioned the torque converter which is possible. Also, the torque converter clutch (TCC). Also, a throttle position sensor could be causing the issues or a vacuum leak.
The items I added would normally cause the check engine light to come on. If it has, have the computer scanned for trouble codes which can direct you to the problem. Most parts stores will do it for free.
Let us know if you have other questions.
October, 16, 2011 AT 11:50 AM
I'll get the codes checked b/c the light has come on while driving between 75-90mph, but then it will go off during the next drive.