Ok, 96 DX 5 speed. A friend's car. Background. Had 360,000 miles on it and it burned an exhaust valve. So it was cheaper to put a lower mileage used engine in, than rebuild that one. Put it in. Now he has this issue with the idle. Hooked up the snap on scan tool and watched the data stream. With the car warmed up (about 205-210 degrees a few minutes ago), it was idling at close to 2,000 rpms. Then, when driving, whenever pushing the clutch in, the rpms never drop to any sort of idle, they stay high (like around 2-3k rpms), and until you actually stop to 0 mph, the idle will drop some. Now when I was watching the TPS voltage and sensor, it was not right. The percentage at idle was 16 percent, and at WOT, it says 18 percent. Obviously not right. Only CEL's it has are one for the the cat (replacing it after this issue is fixed), then a IAC code, cause it had a fluctuating idle when ever you raised the rpms from the idle. Since then, it has only done that intermittently. Anybody have any input? Trying not to buy the throttle body if I dont have to.

 

Is the IACV code P0505? <-- This would fit with the abnormal TPS readings. You can just replace and recalibrate the TPS rather than replace the entire throttle body.

 

code was p1509.

 

Does this code repeat after resetting the ECU? Regardless, the TPS voltage readings say that it is bad.

 

Is the coolant correctly bled of air??
is the IACV clean and working correctly??

 

i reset the codes, going to check tomorrow if the code does come back.
and i found a buddy with an extra throttle body and another buddy with an extra ecu that i can swap and check tomorrow.

have not checked for air in the system yet, but will, and the IACV was just taken off and cleaned yes.