Drivability specialists..I need help!

[BigRedWagon]

Thanks for clicking on the thread. This is my first post on this discussion board. I've been here a couple of times for advice on my 1990 3/4 ton Sub 7.4L TBI. Truck is all stock except for a performance chip.

This has been an ongoing issue since I bought the truck about 2 years ago. When I start the truck cold, it runs very rough and backfires through the exhaust. The longer it sits, the worse it gets (one week is worse than overnight).

I've also noticed that it has really poor mid throttle performance even after is warms up. The idle is a little high, but anything from 10% to about 90% throttle feels like it's running lean.

Here is the list of parts I've put on over the last 2 years:

Complete intake reseal
MAP sensor
TPS
O2 sensor
CTS
TWC
Spark plugs, cap, rotor, wires
ECM (swapped CAL pac chip from old)
Added a performance chip
Fuel pump and filters

I've checked, double checked, and triple checked the ignition timing and fuel pressure. The injector spray looks good. Compression is good warm (haven't checked it cold). Old changed regularly and motor is very clean on the inside. I've had a lot of experience on OBD II cars, but not so much on OBD I cars. I do have access to a scan tool and the integrator is 133 last I checked (running lean, commanding rich). I've disconnected the EGR valve and it still feels like it's running lean (a trick I learned from when I worked at Saturn). I haven't done anything with the throttle body. My next thoughts where to replace the pressure regulator and injectors possibly

Any ideas? I remember my '92 with pretty much the same drivetrain had a similar issue without the backfiring cold start. I installed the complete Edlebrock multi point conversion on it with the same issue (feels like it's running lean)

Oh yeah, one more thing, it has always passed CA emissions testing.

Hope I can get some help. Thanks again for any possible help. I look forward to sharing my knowledge with the board whenever possible