Any part that is new can be bad.
You must make sure that before unplugging it the engine must be up to operating temp, shut it down, wait 1 min or more with the key out of the ignition.
Then you can remove it.
Not doing this will throw it out of adjustment.
You can unplug it, try and run the engine and see if it acts the same.

 

hook up the pressure guage and see what is happening when it stalls. tape it to the window and observe it.

 

What about a fluctuating alternator. The coils work from this source, right. What if the coils are intermittently working. Probably would feel some vibration. Also under load would cause stumble and stalling.

 

After my "dope slap" I have to agree, start simple, check the fuel pressure while driving and see what it reads when it stalls.
If the gauge reads to low when it stalls then its a fuel pump issue.

 

It runs smooth so I assume that the cylinders are firing correctly.

What fuel pressure values are normal for idle?

 

Anything above 30psi.

 

Found an airtex fuel pump new on eBay for $35 so I went ahead and bought it. Getting a fuel pressure tester was more money, I was using tire gauge. I'll let you guys know if the fuel pump fixes the problem.

 

You can "rent" a fuel PSI tester for free from the autoparts store.

 

Have you found the problem?

Mine is doing the EXACT same thing. When it's cold it runs fine, but as soon as it gets to temp it chugs and misses at idle. If I do not babysit the throttle it will die, especially on a hot day.

I have replaced the spark plugs, wires, tested the coil, cleaned ALL electrical contacts, hunted for vacuum leaks. No check engine light, no fault codes. I have not replaced the IACV yet but I have cleaned it thoroughly.

 

No solution yet branch_manager. The parts store near my house didn't have a loaner tester. I'll check another one today. The new fuel pump should be here in a few days.

Yesterday I disconnected the IACV and started it up. It didn't run any different with or without the valve. When I ran without it the check engine light didn't come on. That surprised me, I thought it should have.