Typical 90 3.1 Lumina issue

Starting a thread because I'm sure I'll be back to post more. Car has been stalling often when shifting into reverse from park, but it has kind of always done this and now last week stalled when going into drive a couple times and hesitated when giving it gas to go. Today on the way to work in slow traffic the check engine light came on and the car again hesitated to go and seemed to fall flat on its face but kicked in and bucked a momment later. It did this two or three times while driving at higher speeds in the interstate. I just drove it home from work without incident though so it's not quite doing it all the time.

The only thing I've changed in the last month was the serpentine belt. I bought one that would bypass the AC because the compressor failed on me a few months ago and the bad berings/pully caused my belt to break.

Things that have been recently replaced (w/in last 3-6 months) prior to and during troubleshooting on a bad crank sensor (replaced by a shop when i couldn't find the problem) are as follows: TPS and fuel injectors; previously replaced the sparkplugs and fuel filter. So with these replacements I can't understand what else could cause this. The car has been running fine other than the belt and ac issue for the last few months or more. Yes, I'll probably manually check the DTC to see if I get any readings. Is there a list on this site for DTCs? I couldn't find one searching. Any ideas what else I could be looking at for the problem?

First, there is no way to route the belt on a 3.1 Vin-T to bypass the compressor without making the waterpump run backwards (unless you put a by-pass pulley in it's place). Pull the codes and post here to help us with your troubleshooting. For reference, here is a link to the basic GM OBD-I DTC list:
http://www.sethirdgen.org/dtc.htm

If the cel came on, then you should have a code, that should send you in the right direction.

You might check fuel pressure.

First, there is no way to route the belt on a 3.1 Vin-T to bypass the compressor without making the waterpump run backwards (unless you put a by-pass pulley in it's place). Pull the codes and post here to help us with your troubleshooting. For reference, here is a link to the basic GM OBD-I DTC list:
http://www.sethirdgen.org/dtc.htm
:screwy: oops I guess is all I can say...looks like it's running ok to me though. Guess I'll check it again to be sure. I just used a smaller belt for a model not equiped with AC and routed it the same way except it skips the AC compressor.

From what I can tell it looks like I'm getting 12 and 22 for DTCs. Odd my TPS would be out already. I think I have the old one still that I replaced when I thought it might be bad. Is it possible it could be a different part that's bad?

As for the belt configuration it's running the pullies properly. Not sure what the issue is with that, but the belt I bought fits perfectly

I stand corrected on the belt issue, I guess they did allow for a non-A/C belt routing on the Vin-T, it's the later Vin-M's that didn't.

The code 22 is a TPS code, and it could be tripped by a bad/out of adjustment TPS or a wiring/connection issue between it and the ECM.

From what I can tell it looks like I'm getting 12 and 22 for DTCs. Odd my TPS would be out already. I think I have the old one still that I replaced when I thought it might be bad. Is it possible it could be a different part that's bad?

As for the belt configuration it's running the pullies properly. Not sure what the issue is with that, but the belt I bought fits perfectly

I saw your post yesterday, the belt issue caught my attention. I have the sister engine to yours, 2.8 in a different model. I think the belts are routed the same. As long as you route the belt to the inside of the water pump pulley, it will turn in the normal direction. Looking at mine, I just couldn't tell how much bite the belt would have on the water pump, minus the ac pulley.

I have two belt routing diagrams for my vehicle, one with ac and w/o. With out ac, it shows an idler pulley.

With the belt touching the water pump pulley, if you can turn the pulley, by hand, without much resistance, I'm not sure your getting enough bite?

The tensioner pully comes close to the water pump assembly but allows for you to curve around it so that it's routed properly. I can take a pic of it if people were interested in seeing how it fits and is routed. It's really no different than the diagram except it doesn't go around the upper idler pully(?) prior to going down to the ac pully...though maybe it should? I might be off on my terminology for the parts here but as far as i can tell it seems to be tight enough and no slippage.

I'll swap out the tps when I get a chance. I'm terrible with wiring so if I have to go that route I'll likely take it to a shop cuz I don't know much about checking and testing electrical loads and would likely fuck something up in the process.

I know this may seem strange but make sure your O2 sensors are good, they tell the ECM how musc fuel tospray in the injectors. also check your fuel filter, it may be clogged. let me know how far off I am. I had a car that showed similar symptoms without a CEL until it died then showed a bad O2 sensor. hope it helps and good luck.

how about the PRNDL switch. If the ecm isnt getting the correct signal to what gear its in, it will stall out. Common on ford trucks