Hey guys, my truck was running perfectly until yesterday. When I parked it all was good. I started it up after sitting for a couple of hours and it was idling very low. When I started driving I noticed it was low on power. It seemed to be only running on 3 cylinders. When I let off the gas it backfires. Any suggestions? The check engine light is not on. My truck is a 1986 efi. I'm going to start with the injectors and grounds and go from there.

Cheers,
Paul

 

Popping on decel generally means you're running lean.

 

Some how your timing got off. I would check your ignition timing (cam timing) first and then your crank timing. Your crank timing needs to be at 0* and your ignition timing needs to be at 5*.

If your timing is off, then you need to find out why it went. Probably need to inspect timing chain and tensioner.

 

Also try your valves
Make sure they are set back to spec
Just has the same issues on my 1988 22re pickup.
Runs like a champ again

 

How about checking stored codes first?