Low idle/ occasional stalling In gear, high idle in park

[that_Z69]

Hello everyone, I'm a new member to GMT400, have been searching around the sight but have yet to find the answer/help I'm looking for. I have a 1999 k1500 suburban 5.7 Vortec with spider injection. I recently had a stuck lifter....was ticking like a sumbitch at idle and it increased with revs. One thing led to another I pulled the heads, got it decked and valves reseated as well as upgraded the stock head gasket to a mls style while I'm there. Since my rebuild a few weeks ago I have been chasing little problems. First thing was my timing was off so I got the scanner and set my timing to 0°. She runs pretty good, drive around fine, doesn't throw codes but there's definitely something of, it idle low and sometimes wants to stall at a dead stop in gear. I've replaced IACV, and 02 sensors that seemed bad based off of fuel trim on bank 2, new ac Delco. I've chased all my vacuum lines, hard lines are good, soft rubber is all new. Cleaned/inspected egr sprayed water over all vacuum lines and fitting, didn't find ****. It is measuring air flow so MAF is good, order a MAP sensor for ***** and giggles. I was wondering if anyone could point me in the right direction for diagnosing this. This is my daily and as of right now it's just sitting in the street until I can get it situated. Any help is appreciated. I would prefer information that is diagnosis not blindly changing parts until it just goes away. Thank you.

 

[Schurkey]

I would prefer information that is diagnosis not blindly changing parts until it just goes away. Thank you.

Verify fuel pressure.

Connect a scan tool, look at the data stream. Something is going to be "off" if it's stalling. Loss of RPM signal perhaps, causing no spark. Whatever it is, clues are almost certainly in the data stream.

What does the scan tool show for cylinder-by-cylinder misfire history? Can you control the idle speed using the scan tool to command higher/lower speeds?

How long since it's had a proper tune-up? Cap, rotor, plug wires, plugs, fuel filter, air filter, etc.?

 

[that_Z69]

Turned out to be the MAP sensor. The "People's republic" of China came in clutch with the $12 sensor and prime shipping . Sensor was gummed when I tore down the top end but still worked. The rich condition from improper timing/distributor a tooth off (setting knock retard to zero) gummed it up the rest of the way. was weird because it was getting a reading but I guess what it was reading was incorrect.

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

 

[Schurkey]

I don't understand.

 

[that_Z69]

I don't understand.

Map sensor was the issue and is now fixed. I didn't have the problem before I pulled the heads. Rich condition from improper timing along with it being the original sensor, led to map sensor failure.

 

[Schurkey]

I don't understand why you're putting sealant on the underside of the bolt head, instead of on the threads.

It's the threads that need to be sealed, not the bolt head.

No sealant on the threads--the threads eventually corrode from being wet with coolant.

 

[that_Z69]

It doesn't leak so it doesn't matter. The bolt had a weird radius so I filled it with these sealant. And I put it on the whole bolt, just only took that picture so I remembered the part numbers lol. I've always smothered the bolts for the heads hasn't failed me yet. It's not like it's thread lock it's just thread sealant. First thing you do is flush the oil and coolant anyways so it isn't a big deal.
Did you think I only did the head of the bolt?

 

[Schurkey]

It doesn't leak so it doesn't matter. The bolt had a weird radius so I filled it with these sealant. And I put it on the whole bolt...
...Did you think I only did the head of the bolt?

Yes. That's all the photo showed.