I've tried to find out if others have had the same issue with little success.. When I come to a stop at a stop light, the car unexpectedly revs. It starts bucking for some reason. Now I've noticed that it usually happens when I have the ac on and so I quickly turn it off.. Most of the time that stops it, sometimes I have to throw it in neutral. Its an automatic so my foot is on the brake at a stoplight and that's the only thing going that keeps it from ramming the car in front. I haven't found a clear answer to the issue so I am posting here in hopes that I can fix it. Bought the car used so there is no current warranty. Any ideas and or help is appreciated. Last resort would be to a dealership which means lots of money... Thanks in advance.

 

1) Check intake air boxes. Make sure they are clean, if not....replace with freshies

2) Clean your MAF Sensor. Extremely simple and the cleaner is only $3

3) Do an ECU reset. You can either do the pedal method, or just leave the negative terminal off the battery for 12 hours.

4) If this doesnt work, do NOT take it to the dealer. Ask around in your town for a reputable mom & pop auto shop and have THEM diagnose the possible issue....

 

Please don't take this the wrong way, but are you sure that's not the car just rev matching?

If you're driving in D or DS mode and brake aggressively to come to a stop, the car will step down through the gears, rev matching at each one. If your revs were already high to begin with (braking very quickly from high revs and high speed), then the car will rev match on the way down, causing your car to jerk and your engine to spool up to tag the next gear.

 

I've done the ecu reset. I'll replace the filters and clean the maf today. Could it be oil pressure? Engine check light is not on.

 

That's a possibility. I notice it happens more often when I brake hard. Also more often when the ac is on. Not sure if it has anything to do with oil temp or pressure. I live in central cali so having the ac on is a must because 100 degrees everyday.

 

mine has done this same thing a few times and i'd have to agree with GoFightNguyen on the rev matching thing .

 

The thing is that it doesn't just Rev matches, it keeps revving until I put it in neutral

 

Have you tried cleaning your throttle bodies? I'm just guessing but it is possible your butterfly valves are getting stuck open

 

I watched a video on cleaning the throttle body last night... Looks simple enough so I'll try that today after work.

 

Butterfly valves are always open in this car, they only close when the cars ignition is in the off position. Vvel controls everything.

 

Any suggestions on what it might be then?

 

Changed my filters and cleaned my maf sensor.. Will clean throttle body tomorrow..

 

^ start with that and see what happens, report back if the problem persists. Also could be a vacuum problem.

 

Having weird rev issues in my 08 6MT. Cleaned throttle bodies already and have done multiple ECU resets with the pedal method.

Did cleaning the maf sensor and filters help?

 

follow the procedure on the last page of the link below.
https://www.motordyneengineering.com/manual.pdf

I've done the reset countless of times from different sources. There's a piece of information on step 7 that have not seen in other ECU reset instructions which is when the CEL blinks "slowly" that is when it is actually erasing. I ended up depressing the pedal for more than 10 sec until it stated blinking slowly then i followed the rest of the steps.

Hopefully this helps. please let me know if it does or not.