Got a 90 with a 5.8w in her 93 k. Problem started with a check engine light. Code 33 EGR opening not detected. Being stupid I changed the EGR only to get the same code (oh yea I was also getting 41 HEGO lean at the same time.) Made a post on here and with Steve83's reply bought a haynes manuel and tested all other parts. Come to find out it was the EVP (yes I bought the cheap EGR without a new EVP.)

Now I am having a problem still getting code 41. I think it may be the o2 sensor but I read not to test them. It looks pretty worn I have fiddled with the wires as I have read with no luck.

Now when I put the truck in gear it hunts on the tach between about 3 to 4 hundred RPM diffrence it also does this at a stop light. It also hesitates when accelerating.

I have checked the cap and rotor which seem fine. A through inspection of the plug wires was good except on the right side of the engine the boots are orange and they are black on the left side. There is one in the rear right that is black. Changed the plugs in February pulled them and checked the gap but, the are very black.

Considering changing the plugs and wires.

Any sugestions on the code 41 also any suggestions on the hunting and hesitaition would be greatly appreciated.
Shawn

 

check and test TPS, IAC, Put a fuel gage on the rail do a prsure check, First change the fuel filter. DW

 

Could be a vacuum leak. The solenoids that are associated with the Thermactor (smog pump) and the one that controls vaccuum to the EGR are good places to start.