Basically, I changed the head gaskets and now I have a low idle problem with a vibration. Normally she idles at about 900 rpm, but now its at 625-50. Changing the gaskets wasn't due to overheating or busted gasket. Replaced plugs/wires and o2 sensors. Unplugged my maf to see how it would make the system run. Rpms dropped and without throttle it would die. Took off throttle body and cleaned IAC without messing with the spindle. Unplugged it and then plugged it in also to see if it changed the system, same with the TPS. Manually pressed opened the EGR valve and it dropped the rpms quite a bit. Im looking for a vacuum leak, but cant seem to find one and I cleaned the old spark plugs once then reused them. After little while I took them out when changing for the new ones and I noticed some of the old plugs had been carbon fouled.

I have access to datamaster so maybe someone can take a look and see something my noob eyes can't. I've been working on this for a few weeks now.

 

vacuum leak would bring rpms higher. sounds like to much fuel to me. high or low fuel pressure can do that, failing injector/s can as well. knock sensor count is way up. make sure its pluged in all the way, easy to get it half way on and think its all the way.
here's a shot from mine to compare,

 

You're good people Crab. I've been looking for idle data readings, but I never touched the knock sensors and figured that if they were bad then I wouldn't get a knock count. Did an ohm test on the injectors just now and they all were 12.5 or 12.6 ohm. Shoebox said 12-14. When I was changing spark plugs I remember when I pulled cylinder 7 and it looked wet with carbon fouling. Took a lighter to it and I could see it wanted to light, assumed gas and that it was rich and not full igniting or it had just sprayed without combustion when I turned it off. Thats when I started to look at the EGR system.

DTC - 34 MAP sensor circuit error (signal low indicating high vacuum)
(OBD-1 Diagnostic Trouble Codes)

Thats why I was looking into vacuum, but I haven't looked at fuel pressure besides pressing the schrader valve and listening for my pump. How can a car have a high vacuum?

When the motor is running above 1.2k rpm the motor seems to run quite better, but when it idles or its at a low rpm (stop light) it vibrates and sometimes acts as if it wants to die. Putting a load on the motor seems to change the rpm as well. In park its about 650 rpm, but in drive it drops at least 100 rpm, which increases the vibration. I thought the vibration of the motor would bring up the knock count. Even at higher driving rpm I can just tell its not running correctly. I just know.

 

high vacumm would indicate a intake blockage, like the butterflies being closed to far or the iac motor/valve closed to far or sticking.

 

i would start by testing the map and checking for an open supply wire or shorted to ground signal wire in the map circuit. See that the voltage coming out of the MAP is in spec should be around 1 volt or so at idle and go up with higher throttle opening.Also check with a vacuum guage to see if vacuum is getting to the map.

Do the same with the other circuits you showed codes for. I would also look at a wiring diagram to check ground distribution for the engine management stuff. Throwing all these codes after having the engine apart may be result of a bad ground somewhere and its likely these circuits share a common ground.

I also noticed your IAC counts are much lower than craby's too btw.... it could have something to do with an idle relearn you need to do after haveing the engine apart but im not sure.

It also seems that the computer is subtracting a lot of fuel in the 1800 rpm pic.

 

this is the same as for the lt1. everything except the picture is exactly the same. wires are the same color and go to the same place

 

Forgot to update. I borrowed a MAP sensor and then took my MAF to a friends truck,'98 Z71 2door tahoe, that just happens to take mine. Different MAP sensor didn't change the system and my MAF worked on the truck. Decided that it wasn't sensors and that my optistark was operating correctly being that I back probed them. Got into the fetal position and started crying, then started thinking that my MAP was high in vacuum and why it would be high. Like a mad man I ran to O'reillys and yelled vacuum gauge.

Googled around for the LT1 engine pressure then thought of compression. I'm thinking valves and adjusting them. Cylinder pressure want correct for most of the cylinders, but then 160psi, 100, 90.

 

did you set the lifters with the motor running? at what setting?

 

Yeah, I did it while it was running. Took me a minute to get a hold of it. What do you mean by setting?

 

1/2 turn down after it quit ticking?