rough idle

[rangermike5353]

im trying to trobleshoot a problem with error codes po122,p1120,p1125,po500. these codes popped up b4 i installed a new TPS sensor. after i installed it only po500 & p1125. i tested the voltage from the harness & i got 5volts which is fine. on some of those sensors do you have to turn clockwise 1/4 turn . i installed it with the throttle plate closed. it looks like the only way to get it in there.it idles a little rough and runs fine at low and high speeds but when i slow down and come to a stop or make a left or right turn it wants to die on me . im not sure if the fuel pressure regulator has anything to do with it or the speed sensor(po500) any advice thanks Mike

 

[adsm08]

Care to give some info about the truck? I assume it's a 96, which engine, does it even have an engine, does it run on a hamster wheel, did the hamster fall off the wheel, etc.

 

[rangermike5353]

1996 2.3l 5speed manual. something i want to add . when i come to a stop at low or high speed if i throw it in neutral before i come to a sop less likely it will stall

 

[tomw]

If is does not have a higher idle speed when started cold, I would be checking that the IAC, Idle Air Control, works properly. The cold idle should be above 1k, and slowly settle back below 1000. It should also adjust if you turn on the A/C, if you have it, and when the steering wheel is turned if you have power steering. Well, the older ones did, but the idle should be kept by the IAC anyway.
tom

 

[rangermike5353]

i did a quick test by unplugging the IAC while idling, it stalled which means its working properly. i went ahead and replaced it anyway but still getting a rough idle . still error code p1121 pops up out of range . im wondering do you have to turn the TPS sensor a quarter turn when you install it i know some of those sensors you thx

 

[tomw]

rangermike said:i did a quick test by unplugging the IAC while idling, it stalled which means its working properly.

You make an assumption that the IAC is working when all you did actually was test whether it is open enough, right now, to make the truck idle above the hard stop{mechanical stop of the throttle plate}
You did not test that it can handle the transient load and change of airflow coming into the truck, nor whether it can handle other load changes, and whether it will provide a higher idle when first started cold.
Those actions would re-affirm that it can handle more than holding an idle, which it apparently does, with the engine stable and doing not much else.
I would not pronounce the IAC 'tested' without doing some more tests. The IAC is the part which controls the engine operation with the throttle plate closed, foot off the gas pedal, and it is not controlling your engine to have a good idle. Other items that may affect are PCV system, air intake 'bellows' being cracked, split, or whole, leaky vacuum lines, leaky power brake booster, and leaky EGR valve. Off the top...
tom