'95 DeVille high idle.. 4.9

[Nobody210]

Ok so I've been messing around with my car quite a bit the past few weeks. It started with the power steering pressure hose, which had a leak and was shooting out PS fluid onto the exhaust. I replaced that. There is no leak as far as i can see. Car idled fine after I replaced that. Took it around the block and ran decent. Later that night I took it on the highway and the car started jerking while on the highway. It only would jerk when i would go about 45 or above. Ever since then when I start it, it idles around 2300RPM. I replaced the TPS and ISC with no change. Then I looked behind and saw the MAP sensor connection was not connected. So I connected it. No change. Started it up and left it on for about 10 seconds or so and the car kind of jerked and went back a couple of inches. At that time I started hearing a grinding noise. I shut it off and turned it on a little later and still heard that noise. Haven't started it since. I pulled the codes which are... P022(H) P052(H) I032(C) I052(H) R015(H) T072(C) T027(C) and T077(C). I don't know what I should do next, I just want to get it running well enough to sell it. Thanks for your time.

[procaddytech]

Get the ISC motor ready to diconnect either at the motor or the jumper by the alternator. Open the throttle by hand and press the ISC motor switch closed with your finger. Pressing on the end of the ISC motor shaft should close the switch and cause the motor to reverse and run back trying to bring the idle down. Once it is fully retracted unplug the ISC motor. The throttle should not be touching the ISC and shold be resting on the base idle adjudtment screw. If it still idles high you most likely have a vacuum leak. If the idle is ok, this is where you need to set your base idle, adjust TPS, plug everything in and perform and idle relearn procedure. The jerking at highway speeds sounds like a "fishbite" misfire in lock-up.

[Nobody210]

Does the car have to be on and running when I try to push back the shaft to get it to go back? I tried it with the car off and in the on position n it would not budge.

[procaddytech]

Yes, it needs to be running. The idea is to get the throttle off of the ISC nose switch. with it off the ISC should run out a bit. Hold the throttle open and push the end of the ISC. You should feel the plunger move a little bit (that is the throttle closed switch) and then the ISC should start retracting because the ECM will see throttle closed (you are closing it with your finger) and high rpm. If it runs back unplug it, then release the throttle. The throttle should not be touching the ISC but should be resting on the idle screw. You need it like this to set base idle, adjust TPS, plug ISC back in and relearn idle. We will get to that when and if it runs back and the idle is not high when the throttle is resting on the screw.