Good after noon this is my problem, Truck ran great then it would not run before 10 am after ten fine. It would cough choke run really rough then come out of it, then things went really bad. Have replaced ox sens. coil, map sensor, fuel filter complete tune up, egr valve tests good. Ignition mod new. Now it tries to run when you feather the gas but switches between backfiring through the carb and just not wanting to run. My mechanic said this truck will drive him to drink, and is throwing no codes which he doesn't understand. Any ideas would be greatly appreciated. Also it is a 92 s-10 2wd 4.3 tbi

. My transmission would also not lock the torque converter because it was still trying to "warm" the engine. I lost about 6 mpg also.