I'm having this intermittent issue wherein my 4Runner seems to loose a butt load of its power. It's as if my 4Runner has one of those big drag car parachutes behind it. The issue will either rear its head while I'm already driving, after I have been driving for awhile and I've parked and started driving again, or it will be there on a cold start. It happened again this morning and I couldn't get it up above certain speeds. I could barely get it up to 55mph in 4th gear. I pulled over and both exhaust manifolds were glowing bright orange! I set for about 20 mins to let things cool and came back home and all was fine.

I have read some other threads that say it could be a clogged catalytic converter, lean or rich fuel condition, bad O2 sensor, timing, or our of adjustment valves. However, I couldn't think timing or valve adjustment since its an intermittent problem. My thinking is it could maybe be an electrical problem wiring or a sensor, or a fuel pressure problem. Fuel/Air filters are new/good. I did already do the FSM test to the VAFM and it passed. Also, I have tried to pull trouble codes, but none are in the system.

Wondering of anybody might have any suggestions. Thanks for any help.

Edit: My rig is a 1995 T4R SR5 3.0 w/ a 5spd.

 

At least check the timing; it may be way off but not far enough to cause the problem all the time. A Timing light is $20, the timing value is on the sticker under the hood, and you have to jumper TE1 to E1 to set base timing when you check it.

 

I've had issues with setting the timing already. Took an hour one afternoon and went out driving with my timing light to get base timing set per the hood sticker specs. Fiddled and fiddled around with 8-12 degrees BTDC, and it would run like a beat down dog, and still have this drag shoot power loss issue. It would bog like a slug off the line. I finally figured screw it, and set it 16 degrees BTDC and that was the magic spot. She pepped right up and ran good, the distributor is not off a tooth, but I think the outer ring of the harmonic balance might have rotated or some kind of rotational alignment is off with the distributor gear on the the distributor shaft. But when it doesn't have the power loss issue it runs pretty good.

 

Check your cat for blockage. Might have some stuff floating around in it. You hit a bump and clogs up