1991 3.1 MPFI issues

[Tylerlp]

hey guys i have a 1991 3.1 5 speed beretta and it ran and drove fine from the day i picked it up and it slowly started to act up. after it would sit for just a little bit it would not want to start up again until it sat for about 45 minutes to an hour. Then one day i was driving down the road and it just straight died and wouldnt start again. i had it towed back to my house. let it sit and it start up again and drove fine. after that it kept doing the thing where it didnt want to start so i checked the fuel pressure and it was good and did not bleed down so i factored out having leaky injectors. then finally on tuesday night i drove it to my friends house, shut it off, and it wouldnt start at all. It would sit there and try to run but would not rev up and would die when i gave it gas. every once in a while it would rev up and then just go back down and die. not only that when it does start i could hold it at 2000 rpms just fine and a few seconds later it would start bogging down and die. a couple of times i could get it to idle, but it didnt do it very nicely. after that i replaced the tps, the icm, the coils, the plugs and wires, crank sensor, egr gasket, fuel filter, air filter, ecm, and i even tried dropping the exhaust to see if the cat was maybe clogged and it STILL wont run right. somebody please help it sucks not having the old girl on the road!

[woody90gtz]

Coolant temp sensor will give it way too much fuel if it is bad or has a bad connection and is reading -40F. When the engine is cold it will run rich but run with a bad CTS reading but as the engine gets hotter it runs worse and worse and the reading becomes further from correct. Check the wiring and if you have a spare one throw it in.

[Tylerlp]

ok ill give that a shot. which temp sensor are you thinking the one on the head or the other one?

[woody90gtz]

The one in the intake manifold. The other is only for the gauge.

[Tylerlp]

ok thank you. i should have and extra one somewhere its a two wire sensor right?

[SummitBalt08]

If you need the one off my parts car let me know you can have it

Sent from my EVO LTE using Tapatalk 2

[Berry]

did you check for errorcodes?

[Tylerlp]

it will throw a code for the map sensor if it starts idling (rough) for a little bit

[3X00-Modified]

I'd replace that then too... Even with a rough idle typically a MAP code will not be thrown unless there is something up with it, and since its OBDI the MAP sensor is REALLY important when it comes to fueling since it's speed density calculation using air temp and MAP reading.

[Berry]

which code number was thrown? 33? 34?

[Tylerlp]

it was code number 33