I have noticed something not quite right for a while, but I noticed it more when I drove to Atlanta last weekend. When I apply gas lightly, the car sort of just grumbled at me, and then all of a sudden surged forward, as if it was suddenly catching. However, this only happened for maybe 10 minutes of every hour. I recently changed the plugs, and wires (AC Delco), replaced the fuel filter, and I got a new wp and opti last september. I have a 94, with a little more than 208000 miles. I suppose this may seem trivial, given I still made the 335 miles in 4 hours, but I'd like to fix it. Any thoughts?

 

usually something like this has to do with egr, plugs/wires, opti, coil, or o2's. you could try to get it scanned to see if anything came up. if not, the first thing i would do is change the o2's if they are old. this is what seemed to help my car out the most on really light acceleration.

 

Yup get it scanned, 02s are bad guys.

 

Ok, how long should O2 sensors last? I went through a string of bad ones last summer, but I thought I'd gotten through that. So I guess they're coming up on a year old. That doesn't seem very old in terms of car parts!

 

Look at the EGR.

How's your gas milage lately? If it's suffering than I would look at the 02's if not good chance there ok.

 

This sounds ALOT like a bad EGR valve.

 

tkatchev69: Any update as to what the culprit was? I am experiencing similar problems with my Z...

 

No definite diagnosis yet. I took it to Autozone this morning to have it scanned, but it didn't tell them anything. My SES light has come on occassionally recently, which indicates O2 sensors to me. So I'll try to get at them this week, and see if that fixes it.

 

I have the similar stumble just off idle. SES comes on when driving at low speeds in town about time engine is getting warm. A scan showed a couple of codes pointing to the left bank O2. I'm putting headers on soon so figured I'd wait and put new O2s on then.

Hope you get it taken care of with the O2s.