extreme rich running conditiin

Just finished with a valve job on my 98 2.7l due too intake valves being stuck open because of rich running condition, new all OEM coils, wires, plugs, o2 sensors, struggles on idles, and appears to run fine one the rpm rise above 1000, it foulng plugs and causing a misfire within a few days. NO CHECK ENGINE LIGHT. other then misfire codes when the plugs foul, I thoroughly cleaned the intake plenum, manifold, and throttle body, plus soaked the injectors, any ideas?

 

I assume you have a scan tool, what are the fuel trim levels at idle(long & short)? I would be looking closely at your mass air flow meter as the culprit

 

The scan tool I have is relatively basic, and can not read fuel trim levels, I thought about the MAF sensor, and have tried a remanufactured unit from AutoZone for a couple days, and it did not change anything, so I returned it, I will try to get the fuel trim levels, what are the parameters thatthey're should be reading?

 

Short term should be about +/- 5% at idle
Long term should be + 10-15% at idle

Something interesting you should know is that the check engine light will not come on unless the long term trim is at 24% or higher. Lets say your truck is at 22%, not enough to trigger the check engine light but enough to possible cause your symptoms. Again, assuming all the other parts you've replaced are working properly and within Toyota specs then you might have an issue with the ECU