The truck is acting like something is clogged up, the motor is making popping sound when accelerating. Have changed EGR Valve, C02 Sensor, Thought maybe needs an Idle Adjustment but don‘t know how to accomplish that.
A mechanic friend said maybe need to reset codes in computer...don‘t know how to accomplish this. The fuel economy is not good..
One more thing, the EGR Valve Cylinoid it has 2 holes for air flow...the green hose going to one side of cyloide has suction, there is another white hose that goes to other side of cylonoid. Should it have some sort of air pressure going to it? Haven't replaced, don't know if it is bad.
Thanks for you time.

 

Start out with a new fuel filter.

 

Hello and good morning! I just had the same problem with my 91 truck, I changed everything and then figured out the problem!!!
I removed the computer from behind the driver side kick panel, opened it up and looked very carefully and could see one of the pins had lost contact, you had to find it with a magnifing glass, there was a little burnt area on one spot, I scraped it off very lightly, and put a bit of solder on it!!
All the codes cleared when puttin it back and disconnecting the batttery for 5 min>>>>