Recently I've had bouts of high idle, erratic idle, then times when idle is fine.
Since I recalled ordering an SMP TPS when I fitted the 52mm Holley TB and FIAirgap, I figured it must be giving out.

So I ordered a Delphi TPS for this round.
Changed the sensor this morning and got a CEL with P0122 (TPS Low Value).
Pulled it off and made sure it was orient correctly (it was), and made sure the connector was snapped in tight (it was).
Pulled it off again and fitted the old sensor... no CEL.

Then a light went off in my head... the SMP TPS had the same issue, and wasn't fitted... I'm still on the factory sensor.

I noted all the numbers on the factory sensor;
NL20918
56027940 46435

Searching this I find it is a MOPAR 56027940 TPS.
Depending on where you look, this part is used on;
1997-1998 RAM 1500 5.2L
1997-1998 Jeep Grand Cherokee 5.2L
1997-1999 Dakota 5.2L
And numerous other vehicle/engine size/year applications.


The Delphi part (SS10406) had paperwork in the box referring to 1999 (WJ) Grand Cherokee 4.7L.

Both the Delphi part and the SMP part (TH190T) list as fitting 1998-2001 Dodge RAM1500, 5.2L, and a slew of other motors, including the above mentioned WJ.

My truck was made 5-98, and I believe the 98 year model was superseded by 98½ year model after May 30th, meaning mine is 1997-1998 spec.

Was there a TPS spec change between 98 and 98½?
Am I just receiving dud sensors?
Is there something else I'm missing?

 

Double check IAC screws are tight for the symptoms, just had a similar situation,and yes could be a dud sensor. Or check at a dealership with vin numbers to verify part number.

 

RockAuto are sending a replacement TPS.