I have a 1990 pickup with the 3.0 efi in it. The cel is on and it backfires and the whole truck shakes. It has a lose of power obviously but it only does it occasionally. The problem started happening a couple weeks after I did plugs, wires, cap, and rotor. I just put a new maf sensor in it and that didn't fix it. Does anyone have any ideas because I'm lost.

 

okay, read the code! http://web.archive.org/web/201211190...85diagnosi.pdf
Seriously? Just why did you do that? (and how much did you spend on it.)

 

It has a code 24 and a code 52 in it

 

Other then the sensor you installed that I don't know about, I would go back and double check that I got everything on correctly that I replaced. I would do a resistance check on my new wires as I have had them bad out of the box. Actually a new plug wire was one of the toughest problems I had ever dealt with as I just did not think new parts could be bad when I was a kid.

Make sure you did not knock any hoses or wiring loose when you did your tune up. If it was running fine before you did the tune up, it most likely is a faulty part or something you installed incorrectly, or knocked loose.

 

24 is the Intake Air Temp Sensor(in the AFM). There's an open/short in the circuit. Or the sensor is bad. Or the ECU is bad. Or all of the above.

52 is the Knock Sensor. Which means you have a bad connection in the sensor wiring(the sensor wire from the engine harness to the sensor most likely). Or there's an open/short in the circuit somewhere besides the sensor wire(engine harness to ECU). Or the sensor is bad(not very likely). Or the ECU is bad. Or all of the above.

The first thing you need to do is pull the 15 amp EFI fuse out for a minute. That will reset the ECU. Then run it again and check for codes. Since I assume you never cleared them. And 24 could be stored from before you replaced the AFM.