In addition the info. below, I am going to make a diagram tonight to aid with this that will show my Vac. hose routing.
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The last time I did an idle adjustment everything was in check. My TPS voltage is spot on for the most part .53/54 throttle closed, 4.24 throttle full open.

Now, I have cleaned the IAC out before, checked it again today, it is clean, passages clean. When I cleaned it before and set my TPS, the surging idle went away.

Now, this time I have surging idle, MAF is new as the other was shot.

I unplugged the brown/wire near the distributor, unplugged the IAC and attempted to start car so I could set the driver side screw for the throttle body, car would not want to start, shut right off unless I would put pressure on the accelerator. Not cool.

Up till yesterday, my idle was fine, 1000 cold idle, down to 7-800 warm. In gear, 6-700 rpm.

Right now the idle starts out ok, then starts to slightly move then works its way up to surging bad from 500rpm up to 1100 or so rpm. Any ideas? I have no Check Engine Lights right now, no codes. I should mention that for some reason earlier in the week car threw a 13, 24, 33 and 34 together. Cleared, have not come back. Then yesterday threw a 34 code, wire was lose at one of the relays on driver side firewall, no codes now.

Any and all help appreciated as always. Thank you.

-res

 

No AC, No Heat, No Cruise Control, No Vac Globe on driver side. No Smog but EGR is still in place.

 

Adding a video, will have a second that shows the idle inside creeping up all the way to 1500 or so.

 

Just finished working with it again, noticed that with A,B terminals jumped, the IAC would not turn off. Removed the IAC, it was not inside of the motor completely, so I tested it out, it does retract out all the way so then I then screwed it all the way in. Did the IAC reset process again and then proceeded to do the Idle adjustment. In park, idle is around 1500-1600 rpm. In gear idle is around 800-900 rpm.

Fuel pressure 44-45

Vac is 15/16 in gear at about 800-900 rpm and 19-20 in park at about 1500 rpm

Tested the vac at the port used for brake booster and also at the pass side rear port up top used for my trans vac modulator.

Idle no longer surges. Sooo althought the IAC motor works and all, could it still be failing?

Car does take a blip of the throttle to get it to start now. Feel like I'm chasing my tail.

 

Update: In trying to chase down the demons in the car I just ordered a new Ignition Plus distributor as the current one has a screw that snapped in the base and the whole thing looks worn, should have replaced it when the engine was out before. I also ordered a new set of gaskets for the runners and intake. Any suggestions on what to inspect while the plenum and runners are off? EGR, Fuel pressure regulator? EGR solenoid? Fuel injectors are all in spec I should add. The ignition coil has low miles on it as do the wires, cap and rotor. Don't know about the ignition module, decided just to go with a fresh distributor.

Fired the car up tonight cold, fired up, needed just a bit of help to get it running, it sounded like it was miss-firing, dash lights dimmed as it tried to shut off. Voltage was about 14 steady. Once it was on for 10 seconds or so smoothed out a bit. Just scratching my head with no codes being thrown.

 

Another update: Because the IAC was not retracting all of the way and was constantly on a few times, I ordered a new one and also ordered a new red stripe vacuum modulator for my th350 transmission. Will be installing those tomorrow night after I pick them up.

 

Ok, replaced the IAC tonight, the old one felt busted, moved around a bit in its self.

Went on next to adjust the rpm... the IAC is unplugged, turned the screw in to initially give a higher rpm. Started the car, did not want to start at first then it started, wanted to stall right out. If I would let off the gas it would go down in rpms and stall out. It could not keep minimum rpm. I attempted to turn the screw in more, but it made no difference, the car would still easily stall out if I took my foot (which was slightly on the gas giving throttle) off the pedal.

The first time the car stalled out, as it was stalling out, it produced code 34. Swapped the relays, same result. Misfire bad idle, sound like a big cam, but the vac. is OK.

Any ideas? When I turn the ignition on (before cranking over) the C.E.L is lit solid. Correct me if wrong, normal right?

TPS voltage is good, fuel pressure is good, Vac I assume is good, numbers have been posted, "Vac is 15/16 in gear at about 800-900 rpm and 19-20 in park at about 1500 rpm"

Appreciate it guys, just need some direction.

 

Picked up two BWD/Pacesetter R4005Z relays to replace on the Maf power & burnoff relays.

Replaced those, and then went through the procedure to set the minimum air again. The rpm is still slightly higher than I would like but I can adjust it down a bit more. The idle is not surging now like it was, it does not stall out now and is getting the proper air it seems. Feels smoother, the throttle response seems to be a bit more crisp too.

Now I'm just waiting for the new Fuel Pump relay pig tail to show up to replace this one that has wires hanging super loose and the new distributor from Ignition Plus.

No responses, but if this thread helps someone else, cool.

 

I was replacing the fuel pump relay - pigtail and did not disconnect the battery yea I know Well, I got shocked in my left hand but did not feel it, both times, just a numb feeling. Anyway, after getting everything soldered and sealed tight, plugged it back in and noticed the relay housing was cracked open. I believe I may have shorted/damaged the relay.

Correct me if I am wrong, with the relay plugged in, noticed the fuel pump would run constant, even with the ignition off. As soon as I unplugged the fuel pump relay, the fuel pump shut off. I then tried to start the car again, started fine and idled normal, fuel pump still worked. Is it normal for the fuel pump to operate without the relay?

Just wondering, and again, I know for not disconnecting the ground terminal at least,

 

it can once engine builds up enough oil pressure to close close contacts in oil press. switch for fuel pump.will take longer to start usualy when cold this way though!

 

Interesting, I plugged the new relay in today and the car was hard to start, no priming of the pump and then one I attempted to shut the car off, the pump continued to run. I then unplugged the harness from the fuel pump relay.

With the relay unplugged the car started fine, oil pressure builds fast. Oh and glad i installed gauges, stock oil gauge reads 30 or so psi cold while the new gauge reads about 60 (gauge is installed in a 'T' with the stock style sender at the top/rear of block). Sweeeet. My water temp gauge also was having issues and the new one works like a charm. Any idea why this issue with the fuel pump is going on with the relay plugged in? Wonder where I fried or shorted something. Fuses looked good under the dash.