Sudden Revving

**02C5Rocket** · 07-01-2009, 01:24 PM

Hey guys. My first post on this forum. I was sitting in heavy stop and slightly go traffic, one foot holding the clutch in - the other on the brake, when all of a sudden the motor revved slightly to around 1200 revs, back to idle, then revved to around 2000. It ran like that for a few seconds then dropped back. I was afraid it was going to die, so I caught it and kept it at about 1200 for a moment before letting it go back to an idle. It was hot as H___l that day. I had the air on full blast, keeeping watch on the motor temp which stayed o.k. I did a check and the coolant temp which was at 210 when all this happened. We avoided similar traffic after that, and this did not happen again. We had a 3 hour drive through the mountains back home, using the air on the last half of the trip with no problem. I checked for codes this morning, but all was clear. .........Anyone have any ideas what caused this? Bit of moisture in the gas? Thanks,
Bill

**Dr.Crash** · 07-01-2009, 01:45 PM

has this ever happend before?

**02C5Rocket** · 07-01-2009, 02:09 PM

No. This was the first and only occurrance. No codes in DIC. Runs great! In that traffic, it made me pinch a new seam in my leather seat for several minutes.

**Dr.Crash** · 07-01-2009, 02:15 PM

how long have you had it? could be the heat. could be TPS or dirty maf. check those things out.

**02C5Rocket** · 07-01-2009, 04:44 PM

I have had her since last December. A 65th birthday present to myself. I'm still learning about her. It will be a labor of love to check those items out.
Thanks

**cammed goat** · 07-01-2009, 04:50 PM

Try driving the car without the AC running. Could be the AC activating/cycling causing the idle to drop then raise.

**Dr.Crash** · 07-01-2009, 07:18 PM

Originally Posted by cammed goat

Try driving the car without the AC running. Could be the AC activating/cycling causing the idle to drop then raise.

another good reason

**JoshieDoom** · 07-02-2009, 02:44 AM

Originally Posted by cammed goat

Try driving the car without the AC running. Could be the AC activating/cycling causing the idle to drop then raise.

This is most likely it actually.

Clean the IAC valve on the side of the TB as well if you feel froggy.

**02C5Rocket** · 07-02-2009, 05:28 AM

This was the first time I used the A/C in combat conditions. Before this trip, I had it on only for a few moments to see that it cooled. The top has always been off when I took her out. I had not thought about the A/C cycling causing the rev. I'll check all of the above. Thanks.
Bill

**02C5Rocket** · 07-02-2009, 12:25 PM

After spending quality time this morning with my Rocket, If I had to blame any one item, it would be the TB. It was really dirty. I cleaned it and the peripherals, and after a test drive, all seems fine. Since I only had the one occasion of an idling issue, the only thing that I immediately noticed as different is a much improved throttle response. Absolutely no lag. This was one of those things that crept up, and really didn't get my attention as an issue, since Smoky is in all the bushes around here. I looked at the TB, MAF and filter when I first brought her home. All looked fine then. I was really surprised at how dirty the TB got in 6 months. Thanks all for your help.
Bill