Strange problem - throttle revs itself

[repenttokyo]

After participating in a 5 hour rally this weekend, my throttle has developed an odd habit. When I am driving normally, everytime I shift gears, as soon as I put the clutch it the engine revs up about 500 rpm and then starts to drop normally. It does NOT do this if I rev it in neutral and the take my foot off the accelerator. I checked the throttle cable and it's not catching on anything....any reason why this would only happen while the car is in gear? Is there some special return spring or something?

[Ross]

Keep looking around the throttle cable I say. Maybe something binding with the engine torque.

[bill g]

Make sure the engine/transmission is not moving about excessively due to failed engine mount - this was a cause of that problem on previous car/s I have owned.

Bill G

[repenttokyo]

that is something I hadn't considered. Should I be checking for engine vibration at idle?

[repenttokyo]

would a bad engine mount ever manifest itself as a rumble sound heard only inside the car, at idle? The sound lessens as I drive, but I thought it was due to a hole in my exhaust from too much deep snow a few weeks back - now I am wondering if it is vibration from a bad mount? What is the best way to test for a bad engine mount?

[Incantation]

maybe your dk is sticking

[repenttokyo]

maybe your dk is sticking

what is a dk?


it seems to only be getting worse, especially around 2k-3k rpm. It almost only happens on upshifts, when I release the accelerator before the shift. It's almost like having cruise control on all the time. Not the safest thing in the world. I took some silicone lubricant and sprayed the throttle linkage on the side of the engine, and the throttle wire. I noticed there were 2 wires - the throttle and then another one beside it that seemed a bit loose. What is this second wire? They seem to move in tandem.

[Blitzkrieg Bob]

what is a dk?

thats a drive by wire throttle body system.

[repenttokyo]

to clarify, by "wires" i meant cables, as in throttle cable.

[Blitzkrieg Bob]

to clarify, by "wires" i meant cables, as in throttle cable.

Potentiometer on the pedal driving a motor on the throttle
Body.

You’ve got a good old fashioned boden cable. much like a bike.