Help; Idle and drivability

[Dan H]

Hi all, I need some help with my 95 MTX. Idle is very erratic; sometimes normal, sometimes a bit too low and rough, often stuck at about 1400, sometimes stuck at 2k, sometimes races to 3500 when eatc (a/c or def) is ON. A few times while driving, the engine power fell flat on its face while engaging clutch from stop or from 1st to 2nd. (Engine did not die however).

Only code was 122, TPS (stored), replaced TPS, same problem - now the codes are 121 and 122.

Could this be a CID, VSS, or maybe a CCRM problem? I am confused as to why the EATC changes the strange idle behavior.

Any help appreciated.

Thanks,

 

[Dan H]

Just thought I would add that the IAC was replaced about 1 year ago (less than 5k mi), and I have performed the idle reset procedure multiple times.

Please help. I do not know what to do other than start changing parts.

 

[NotSoSlowSHO]

Have you pulled the codes yet?

It sounds to me like a TPS (throttle position sensor) is on it's way out.

You could very well have MAF (mass air Sensor) problems too.

And I wouldnt rule out a vacuum leak :wave:

 

[Dan H]

Yes, I pulled the codes 3x. 111 & 122 (stored) were the only codes at first. I replaced the TPS and now I am getting 122 and 121. Both TPS codes. What else can throw a TPS code?

 

[NotSoSlowSHO]

A faulty TPS harness.

 

[NotSoSlowSHO]

Another thought, and another sensor to look into that contributed to idle control...

VSS Vehicle Speed Sensor. Located on the throttle cable housing of the transmission.

 

[itwonder]

Are the clamps on the air inlet hose between the throttle body and the MAF assembly tight?