Stumble, Hesitation, Bucking, Hard to start, Stalling, backfire, jerking - My truck: 1989 Chevy K1500 5.7L 350 4x4 V8 I'm new to this forum so forgive me if I break ...

My truck:
1989 Chevy K1500
5.7L 350 4x4 V8

I'm new to this forum so forgive me if I break any rules. My truck randomly stalled on me about a week ago. Very shocking because it's never done that. A few days later it began to stumble and hesitate upon acceleration. During idle it would sound as if it were about to shut off but it wouldn't. Rough idle and hesitation sounded like a vacuum problem, so I checked the TBI. The EGR valve was faulty so I replaced it. That fixed the rough idle and it drove fine for a day or two. But then yesterday and today, my truck began to buck pretty hard. I was driving down the interstate and it started stumbling, bucking and I heard a misfire or backfire. It's was very cold here in Georgia but I don't think that has anything to do with the trucks behavior. It was also hard to start for the first time in 3 years. I had to pump the gas pedal to get it to start. Over the past years this is what's been serviced: remanufactured engine, rebuilt transmission, egr valve, drive shaft, battery, brakes, tires, water pump, catalytic converter, muffler, fuel filter, and thermostat. I pulled codes off and this is what I got 32, 42, 43, and 44. It bucked and jerked around for about 30mins. I parked it for about 40 mins and then it drove fine. Here is what I think the problem maybe:

1. EGR Solenoid
2. Fuel Injectors
3. TPS
4. Fuel Pump

I don't know what else it could be. Any ideas?

PS: This truck is my baby!!

Could you have gotten some bad gas (water)?

Spark could be right but if it is jumping and having that much trouble then you have more than bad gas. Good places to check would be fuel filter very cheap fix. supposed to be changed every 5k but no one does. Also might be cap and rotter. I had a old truck that did that until it stalled out and that is what it happened to be. I may be wrong but i dont think the 89 has fuel injectors?

It sounds like a spark problem, although, those engines are notorious for the intake manifold gaskets leaking. Check the fuel pressure and flow rate as well to see if it is within specs.

I'm sure its not the spark plugs. Had those changed by a professional shop in February when I changed the engine. I also changed out the fuel filter the day it stalled. The 89 has 2 fuel injectors. It's a TBI. Bad gas? Ive been getting gas from the same place for a year. I doubt it.

Also, I just went out and started the truck up. It's about 23 degrees outside. It started with no problems. It appears to b idling fine. What do I do if it is bad gas?

Okay, after about 45mins of driving, this is what was going on. the engine drove fine. the problem this time was with the transmission! It would not kick back down or downshift properly. It would just cause the engine to rev and rev. But after about 10mins of that, it went away. The truck drove fine....except when I was going on a steep steep steep hill. It did sputter and buck just a little bit. I'm now wondering if there is anything that controls the timing between the engine and the transmission? What component can go bad and cause the engine to stumble and the automatic transmission to not downshift?

Clutch packing's could be warn to bad, or maybe torque converter which is essentially a pump on the shaft of the engine that uses fluid pressure to turn the transmission instead of a clutch like on a standard type trans. Recently i had a friend who was having some problems kind of like that and it turned out to be a loose wire harness to be best case scenario.

The lockup converter could not be unlocking, which would act like a manual transmission if you were slowing and not down shifting or not pushiong the clutch in. It may have a bad tcc solenoid.

Drove it again for about 30mins. Engine was fine. Just stumble during uphill acceleration. However, the transmission was still sooooooo bad. It wouldn't go past 20mph. I'm going to take my Chevy to Mr. Transmission tomorrow afternoon.