91 navajo acting evil

[BlakeOfDoom]

I've searched and searched and cant find anything with my truck's symptoms. I recently replaced the heads and since then nothing has been acting right.

The engine sounds like it is having a tough time when I fire it up, it is hesitant to start and takes a try or two.

The idle in park is smoothish, it still feels a little off, when I push the accelerator in park the throttle response is not smooth.

The engine runs consistently above 1500 rpm, no misfires or knocking or anything.

When I let off of the accelerator I get a pop or two coming from the engine.

when I put it in gear the pitch from the engine gets lower and acts erratic, like it is having a hard time being in gear; not drivable.

I have listened to all the exhaust valves and injectors with a stethoscope, everything sounds uniform and nothing seems off.

I disconnected the maf when the truck was running and there was no difference.

I loosened, but did not remove the exhaust crossover to ease the pressure in the exhaust system (checking for a plugged catalytic converter) no difference.

I sprayed starting fluid in the engine bay when it was running to see if there was a vacuum leak, no difference.

The check engine light is not on during any of this.

all electrical connections are in place and nothing is loose, The heat riser tube is not connected but that wouldn't make a difference.

I am at a loss at what this issue could be. Are there anymore tests I can run to help me with this problem?

I am absolutely lost and have no clue what is causing this.

 

[MrShorty]

I would probably pull codes, even if the CEL isn't coming on. There might still be useful information in the computer. I would probably also check fuel pressure to make sure fuel delivery is where it should be.

 

[BlakeOfDoom]

something stuck in the valve train?

I'm wondering If the new heads I put on might have something sticking in them; like a lifter or a sticky valve. would running some marvel mystery oil help solve this dilemma?