Surging

[Cokeroker]

Anyone know what could be causing my surge problem? I have a 2000 Grand Prix SE. Have replaced the battery, the gas cap, transmission flushed and filled, fuel injection cleaned, fuel filter, and the Throttle Positioning Sensor and the surge came back. It varies from 2000-2500 RPM when it does it so you can imagine that it definitely can be felt. It mostly occurs in a slow acceleration. Goes away when I kick it down into overdrive passing someone. Help

[Ripn12s]

could it be misfiring??

[gtp 2000]

i agree with the previous statement, it could be a misfire of some sort

[Cokeroker]

the plugs are only like 40,000 old... same as the plug wires.... you guys think that maybe a bad plug or wire.... maybe worse.... a coil?

[mytwopointeight]

my s-10 did that and it was a vaccum leak, i dont kno very much about Grand Prix's but that might be it

[roberts5]

My 1999 GP GT is doing the exact same thing. Have you fixed your problem yet? If so, any info would be appreciated.

Thanks,
Greg

Originally Posted by Cokeroker

Anyone know what could be causing my surge problem? I have a 2000 Grand Prix SE. Have replaced the battery, the gas cap, transmission flushed and filled, fuel injection cleaned, fuel filter, and the Throttle Positioning Sensor and the surge came back. It varies from 2000-2500 RPM when it does it so you can imagine that it definitely can be felt. It mostly occurs in a slow acceleration. Goes away when I kick it down into overdrive passing someone. Help

[supreme_style21]

Hmm.. I am also experiencing this. I was going to throw a TPS at it, but hearing as how it didn't fix your problem, I'll hold off for a bit. I've got brand new Delco plugs and wires, fuel filter, and one coil. Are you noticing it get progressively worse? Mine is at the point to where I'm very hesitant to drive it.

[hoopsGTP]

I Have a 2001 GTP that does the same thing. Surges enough to see the RPM increase 200-500 RPM, disengauge TCC and problem stops. HAve installed Wires, Plugs, FF, AF, PCV, Inspected for Vacuum leaks, Vacuum 20inHg and steady. Tranny died, so swapped in a new one. Still has original issue. No codes, Scan tool reveals nothing of misfires(even slight ones) or EGR, or TPS eratic. TCC Slip is 66-120 RPM under a load. Pulled off Trans Side cover and replaced the TCC pressure regulator O-Ring per TSB. Fuel economy dropped from 28 MPG to 21.3 MPG and that aint because my foot is init either.. Thoughts????

[doctorhrdware]

Are getting a check engine light. If you are, you need to pull the DTC and post them if there is any.

[richtazz]

Pull the IAC valve off of the throttle body and inspect it's pintle as well as the bore it rides in for excessive carbon deposits.

[hoopsGTP]

No DTC's, Pulled IAC out and all looks fine, no excessive carbon. I found that when I am running around say under 70 MPH the TCC engages and disengages, but say above 80 no problems, except a vibration. The surging occured before tranny replacement and after with two different TC's. I think it is PCM telling TCC to disengage, but why? what could be telling it that, I have looked at all sensors, misfires, MAT, MAF, IAT readings all looks OK.

[tblake]

How long ago were the plugs replaced? What brand? What Gap?

[hoopsGTP]

Plugs less than 10K miles, Plug Wires less than 10K miles and all GM. set to the gap listed in the SM. I think it was .060. Pulled and inspected about 1K ago, no carbon tracking on insulator nice and clean on the tip.

[tblake]

were they delco iridium's? 41-101's? I've heard of delco plugs lately having issues with the porcelin cracking causing issues like you describe. I hope they weren't bosch, Rich can tell you all about Bosch. Same with delco rapidfire plugs.....

[hoopsGTP]

UM, I believe they were the Iridiums, 41-101. I thought they were made by NGK though and resold to GM. Any idea what I should place in there as I was going to replace with NGK or Rapid Fires.