Ordered and installed a new IAC valve. The van never ran so good for about an hour. While on the highway I felt a surge and the engine light came on. Then every so often I could feel the engine surge off and on while I was doing 60 mph. Van did idle when warm which was my original problem before replacing the IAC valve. Should I try the finger trick again? How do I get the code for the engine light?

 

The surging problem sounds more like a bad TPS sensor instead of the IAC sensor. Autozone will check your codes for free.

 

The code I am getting is P O 121

 

Bad TPS sensor.

P0121 (M) TPS Voltage Does Not Agree With MAP TPS signal does not correlate to MAP sensor signal.

 

Thanks bwdakrt. I noticed someone posted a fix by drilling a hole in the sensor to clean. Would you try this, or just get a new one?

 

Get a new one. The electrical part inside the sensor is fried.

 

^X2! The cleaning of the current one, if it worked, would only be temporary.

 

Should I disconnect the battery when changing out the TPS?

 

You could do that even though it not necessary but I would recommend doing it after the change to reset the PCM. Before or after...your choice.

 

Installed a new TPS and took the van on the highway. Ran great with no surging problems. Thanks for the help !!!