I just had my motor rebuilt by a reputable performance shop, and then tuned by one of the best in the region. After picking the car up from the tuner, I drove it about 20 mins and then started experiencing an issue under mild acceleration.
Under "light load" the car drives/performs well, and under moderate throttle (40%+) it pulls good. Right around light acceleration (10-20% throttle) the car starts to "buck" and the tach "flicks" from 3k rpm down to 2500rpm repeatedly. When crusing at 50 mph, if given slightly more throttle from 20% the car may downshift (automatic) between passing gear and back into 3rd repeatedly until either more throttle is given thus keeping the car i passing gear, or if throttle is left off it will stop bucking.
Other than this, the car runs beautifully.
During tuning, the shop and tuner applied a mod (shimming maybe) to the CAS to make it run smoother. THe tuner said that he did not experience the bucking anytime during his 6 hours of tuning. I brought the car back to him to run data logs while I drove it, the AEM did not indicate it was losing a signal from anything...and everything else with the tune seems to be "fine." As far as he's concerned it's not a tuning issue, and probably an electical issue. It does seem as if the car is losing a signal or maybe shorting out temperarily.
The performane shop spoke with the tuner, and will be taking it back for troubleshooting next week, but I wanted to see if anyone on here has experienced something like this. Likely, because it's an AEM, the car is not throwing codes.
Is it maybe a sensor loose or broken? The CAS is brand new...?
Is it an issue with the transmission? The tranny builder looked at it yesterday, and said he was pretty sure it wasn't the transmission. The built transmission has been working fine for over a year now...
I'm at a loss atm. Any suggestions on where to start would be good.
Thanks in advance.
Under "light load" the car drives/performs well, and under moderate throttle (40%+) it pulls good. Right around light acceleration (10-20% throttle) the car starts to "buck" and the tach "flicks" from 3k rpm down to 2500rpm repeatedly. When crusing at 50 mph, if given slightly more throttle from 20% the car may downshift (automatic) between passing gear and back into 3rd repeatedly until either more throttle is given thus keeping the car i passing gear, or if throttle is left off it will stop bucking.
Other than this, the car runs beautifully.
During tuning, the shop and tuner applied a mod (shimming maybe) to the CAS to make it run smoother. THe tuner said that he did not experience the bucking anytime during his 6 hours of tuning. I brought the car back to him to run data logs while I drove it, the AEM did not indicate it was losing a signal from anything...and everything else with the tune seems to be "fine." As far as he's concerned it's not a tuning issue, and probably an electical issue. It does seem as if the car is losing a signal or maybe shorting out temperarily.
The performane shop spoke with the tuner, and will be taking it back for troubleshooting next week, but I wanted to see if anyone on here has experienced something like this. Likely, because it's an AEM, the car is not throwing codes.
Is it maybe a sensor loose or broken? The CAS is brand new...?
Is it an issue with the transmission? The tranny builder looked at it yesterday, and said he was pretty sure it wasn't the transmission. The built transmission has been working fine for over a year now...
I'm at a loss atm. Any suggestions on where to start would be good.
Thanks in advance.