Question : surging

[TheOtherStyle]

Got a car coming my way to work on, 96 Cutlass Ciera, 3100. Recently got new plugs and wires, some other misc maintenance.
Problem is that its surging. At idle it goes up and down. Guy said Advance pulled the codes, and while he didn't have the exact codes on hand, he says they told him camshaft position sensor, o2 sensor, and MAF.

I'm thinking it might just be a vacuum leak, as I saw some things under the hood when glancing at it today that looked like they could use replacement.


Any suggestions from you guys?

[TheOtherStyle]

Anybody?

[Skeith]

is it surging or loping? an energetic increase in RPM or gradual fluctuation?

I had a similar issue with the 3.1 MPFI in my Lumina. It would fluctuate in rpm (about 2-300RPM) at idle. Turned out it was a combination of a bad throttle body and O2 sensor.

loping is basically designated as the engine RPM dropping below its nominal idle RPM (usually around 800RPM or so) and then back up to its nominal RPM. Surging on the other hand is the engine exceeding its nominal idle RPM and dropping back to nominal or below nominal.

if surging i would look at the idle air control, TB and vacuum as vacuum leaks -usually- result in a higher than nominal idle. This could also include the MAP sensor, PCV system.

if loping i would look into the IAC, TB and O2. In most cases i have encountered, a bad O2 sensor caused loping instead of surging. It could also be the EGR as well.

This is of course from experience, a more educated suggestion may be available.

any way of getting the codes? having an exact code(s) could help significantly.

[TheOtherStyle]

It's surging. I don't have a way to get the codes at this time, I can only report what he told me.

[Skeith]

Have you tried unplugging the MAF sensor to see if it will run better?

[TheOtherStyle]

Not yet. I saw the car in person, observed how it was running, and figured I'd get some suggestions what to check before I went and looked at it to try to fix it