1990 K1500 with 350 TBI and 5 spd manual.
When driving down the highway today, my shift light came on when I was completely off throttle, followed by a SEL that would come and go. Completely lost all engine braking and a steady rpm at idle of 1350. Is this an indication of a bad TPS or is something worse going on? I do not have a OBD1 reader and don't really feel the need to spend the cash for one seeing as this is the first SEL me or the previous owner (my dad) have seen in the 20 years of either of us owning it.

 

not enough info to call a part
you should be able to read the codes by grding the dlc. the codes will flash out on the cluster....count the flashes on the ses light. google it and when you find the codes...post them here.

 

The light never flashed. It stayed on for a few miles, then went away for a few more. Rinsed and repeated for the entire 15 mile ride home.

 

@Gold Truck I may be incorect, but I thought some OBD 2 readers can read OBD 1 codes. You might be able to find a local parts store that has one that they can use and tell you codes. Or they might still have an old OBD 1 unit.

 

@Mr. Dude with a face I've checked local auto shops and because of covid, nobody will read codes right now. On top of that, they said even if they could, none of them have an OBD1 scanner. Oreilly has one for purchase but with a $300 price tag, I don't know if I'm ready to shell out.

My truck has the old box port, different pin layout than an OBD2 scanner. Would require a new one.

On a side note, anybody got an OBD1 scanner for sale? 😁

 

Bought the scanner, plugged it in. No codes were found.

 

test drive the truck...when the problem occurs read the codes immediately without turning off the truck.

 

Scanner finally picked something up. Code P0122 Throttle Position Sensor 1 Circuit low voltage. Twas what I thought it was, but I'm still learning how different bad parts can effect different things. Thanks for replying everyone that did! I appreciate the help and surely some day you will see me again in this same forum!