hi all, just bought a time capsule of a truck. It is a 90 f150xlt lariat. It has 103k miles on it, 6cyl, auto, 2 wheel drive. I have been going through some trouble shooting with it because it had sat since before thanksgiving. I have replaced the following
fpr
fuel pump
plugs,cap,dizzy
act sensor
coolant temp sensor
f filter
o2 sensor
While I had the tank down I looked at the tank and it was clean but fuel was a little stale, and I have ran at least 2 tanks of fresh in it. After I did the o2 sensor I did an obd 1 test on it and the koeo test was clear (no codes), the roer test still shows the o2 being lean. Can someone help me out on this.

 

Check for vacuum leaks with some carb spray, check around the intake manifold where it meets the head as well as the throttle body shaft for the butterfly. And the obvious vacuum lines. If no leaks are found run a compression test on the engine.

 

ok, will check the vacuum tomorrow, it has been on my list. It will run really good sometimes and seems to be getting better the more I drive it, just figured all the nonsense would have ran through it by now (bad gas). Thank you for a quick reply, anyone else? Could a eec solenoid do this?

 

vacuum was good and compression is strong and equal. Any other ideas?