The TPS on a 12V is only there for auto shifting points , and the manual trucks don't even come with one.

 

Well, the OP has an auto and the TPS replacement helped on my 12v.

Edit: I was thinking '94 with different pump.

 

Thanks Oliver. Sorry I wasn't clear -- yes, when it has been sitting for a couple of days, the engine cranks away without starting.

I still need to drop the fuel tank to replace the in-tank fuel gauge sensor -- am I likely to be able to locate a leak when I'm completing said chore? (My guess is it must be a tiny leak if it takes several days for the air to get into the system.)

 

When my '91.0 was acting like that I found a loose band clamp at the end of my fuel line , near the motor, that was allowing fuel to drain back to the tank. It acted exactly like you describe. Hard starting and a little white smoke when it did start, after sitting for more than a day.
It could be at any point from the tank forward...pin hole in the fuel line, cracked connector, missing / broken clamp.
You might want to consider the option of replacing the fuel lines and clamps when the tanks is down depending on what they look like.

 

This truck is going on 24 years old and I feel that an expenditure for replacement of ANY old plastic or rubber part is money well spent -- so it is my strong preference to replace the fuel lines. But those parts ceased to be available from Mopar long ago -- do you have any particular recommendation for an aftermarket source? Thanks again for the help and I apologize for these pesky questions.

 

I bought an FSS from Hans Auto a while ago. NOT a Bosch product. Definitely Chinese looking. I bought it as a back up but have since switched to manual shut off.


My 2nd gen acted like this when a return line cracked. I parked on gravel so it was hard to notice a leak but I could smell it. Truck sat over night or a couple days and took longer to start than it should have and smoked a bit. After the initial start it stared like it should for the rest of the day. This got worse over several months.

 

I used an old fuel cap and drilled it out and threaded a male air fitting into it put about 10 lbs of air on it let it sit for 10 or so minutes followed the lines presto leak where PO had spliced the line together fixed that has been fine ever since

 

Glad you found it and it was a relatively easy fix.