ya should be the same under load as it is idling. should see at least 14.5psi and it really does not hurt if it is higher than that. the pressure regulator on the TB makes sure the pressure drops down to exactly what is needed.

 

Ran the codes

12: NA
17: engine temp to cold (thermostat)
21: o2 sensor
37: ttcs or ttsv
41: generator field not switching properly
51: leab idle (o2 sensor)
55: NA

Definetly need to replace o2 sensor, and thinking get a warmer thermostat. However, can someone explain codes 37 and 41?

 

almost sounds like you might be having a o2 sensor issue if you got 2 codes popping up. NTK sensor are the best but i think if you use anything other than the bosch sensors. i think the bosch ones get clogged up because of the bad design and fail early.

 

Ill start by replacing o2 sensor. What about the other codes? What temp rating of thermostat should a 90 318 tbi have

 

should have a 195*f thermostat in it. i would maybe wait and see what the o2 sensor does. the other codes might have just been 1 time codes. i usually erase codes run the engine and check them again to see what ones are important since the important ones will pop right back up again.

 

Ive had the 37 code before. Never the other ones (besides 12 and 55 obviously) then again i havent ran the codes for a few months

 

code 37 can be like a ghost code in most of these trucks. it usually shows up on most of them until they actually started using the electric lockup torque converter in the 46RH