Runs good until warm then back fires n spuders when giving it gas. Ive check the cat cause the manifold was glowing red on the back 2 cylinders. New filters lines tank has some crap in it but still getting fuel it seems. I changed the computer from a 88 auto truck wondering if that matters I feel like ive tried everything . The two plugs show it running lean n the truck has great compression....so any ideas would be nice

 

I had this issue with my '85 runner a few years back. I figured it had to do with a short in the wiring somewhere since everything checked out other wise.

So I bought a parts runner and swapped the entire wiring harness, headlights to tail lights into my truck.

Problem solved, pretty drastic though.

I'd say look into the engine harness for problems. Check the spot where the fuel injectors join together for corrosion or broken connections.

 

Your going to have to pull the MAF box and imitate the motion of running while watching injectors for fuel delivery. Remember, start with simple FIRST otherwise your going to regret having an old Toyota. You may have clogged near 30 year old injectors. Get 4 jars and place injectors in cutouts at jar lid, pull MAF and cycle it with injectors in the jars and ignition ON. This will give you a good preliminary start to go from. These injections systems are dated. Are you pinging? Power loss? How about dont drive till this is sorted out or you will surely drop a valve.

This happened to me and it was due to weak #2 and #4 injectors. Remans are available at Rockauto for $27/piece. Unfortunately Im still dealing with elevated egts and high NOx and cant figure out why.

 

The behavior you are experiencing sounds like what happened to me when my TPS failed. Truck ran fine cold, on warm up idle was high and if I pressed the gas notably the truck sputtered, backfired, and lost all power.

Checking the TPS is easy if you have a feeler gauge and ohm meter:
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml