My 22re '87 4Runner has been acting weird the last few weeks. First off the idle will vary sort of randomly. Sometimes it will be up at 1200 and other times at 800.

Also, when I go to climb up a hill, sometimes it will all of a sudden lose power, start missing (stumbling, running rough), and barely make it up the hill. Same thing if I'm pulling something. It will act fine and then all of a sudden go into a mode where it misses and loses power and then when I get back on a flat section it "catches up" and runs fine.

It doesn't seem to matter if the engine is hot or just started, it does it in both cases.

I'm pretty sure that when the idle is high (1200) it has normal power and when it's low (800) is when its losing power.

It needed new spark plugs so I just put those in and that pepped things up (faster acceleration, etc.) but it still does the same thing.

Any ideas here to dial in the cause before I just start replacing things?

 

Has the check engine light come on?
Even if it hasnt, check the computer for codes. If there are none, pull the EFI fuse to reset the ECU.
Make sure the timing is at spec.
Check all fluids.
Visually check the spark plug, ignition, etc WIRES for defects, cracks, burns, etc.
Is it an auto or manual tranny? Are you down shifting if its a manual? is the tranny down shifting when going up hills if its an auto?

 

Have you ever replaced the fuel filter ?.

 

Thanks for the advice.

Ok, I plan on replacing the cap, rotor, wires, and fuel filter today. I'll also adjust the valves and check the timing.

No CEL is coming on though I need to double-check that it's not disabled or something (I bought the vehicle used a few years ago). I'll also reset the ECU.

We'll see how it goes