Recent tune, but now getting terrible surge and dead spots in the powerband. SES light comes on and throws code P0121 TPS. It also drops to about 400 RPMs and wants to die when I stop, then returns to normal idle. I have cleaned my MAF, which was filthy but had same outcome. Also, I can unplug my battery and it will run fine until the SES light comes on immediately followed by my TCS light after about 45 min of drive time. I have read the gear chatter post but dont have access to a vacuum meter or scan tool to do the troubleshooting. I do have a multimeter. I have always researched and found all of the solutions to my problems but need help on this one. Thanks for any input.

 

Any help/suggestions would be really appreciated.

 

you need to find a scanner you can put on it that will show tps percentages, since that may be at fault. Is it a tps circuit or low voltage code?

 

Have you changed the TPS........

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it was code p0121 for TPS circuit. No I havent changed it yet, wasnt sure if that was actually the cause of the problem. Do they go bad that often?

 

Finally changed the tps. ran great for about five drives, then back to ses light. Same code Po121. Thanks

 

You should be able to diagnose this one with your volt meter. First, with the ignition on, ensure you are getting 5V at the gray wire on the TPS. If yes, check the voltage at the blue wire. It should range from approximately .7V at closed throttle, and go up to 4.5V at WOT.

Report back with your findings.