Stalling out

[spado123]

I got an 89 full size with the 351 in it and efi. in the mornings it will start up just fine run for about a minut then the rpms will start to bounce ually down and then it stalls out, sit for 5 seconds and it repeats for about 20 minuts then it runs just fine. no such problems in the late after noon once it has warmed up. i did the plugs, wires, cap and rotor, ignotion coil, adjusted the timing so it is set properly, new fuel filter, and fuel pump and relay work just fine. was told to check for vacum leakes so i went out and bought a can of either but couldnt find anything on the lines. it started after a long trip took it off cruise and the first down shift it spit a little smoke but i havent had any smoke since. it seems to be running a litte rich, i got that black haze on the plugs i pulled out but it doesnt throw any codes. i took it to a shop and they hooked up an OBD 1scanner on it and coldnt pull anything. any suggestions?

 

[Rons beast]

Hey Spado, Welcome.

Since the plugs are black, and you have the occational black smoke, that is a sign of a rich condition.

The 2 thoughts I have are the temp sensor is reading too cold and telling the ecu to make the mixture richer. Then as the truck heats up it's slow in getting proper readings to the ECU.....OR the o2 sensor is going south.

You could take it to a shop and have them see if they can read the 02 sensor, but if it's really old, I'd just change it. The truck is 23 years old. I bet it has everybit of 100k miles on it. Same with the temp sensor.

Good Luck

 

[spado123]

Hey Spado, Welcome.

Since the plugs are black, and you have the occational black smoke, that is a sign of a rich condition.

The 2 thoughts I have are the temp sensor is reading too cold and telling the ecu to make the mixture richer. Then as the truck heats up it's slow in getting proper readings to the ECU.....OR the o2 sensor is going south.

You could take it to a shop and have them see if they can read the 02 sensor, but if it's really old, I'd just change it. The truck is 23 years old. I bet it has everybit of 100k miles on it. Same with the temp sensor.

Good Luck

Awesome thank you and i will look into those.