Jbinman

I bought a 1990 3.0L 4runner. The body is in great shape, but it's obvious they only fixed things when broken...no PM.

Anyway, this car idles rough when stopped at a light. The whole car "chugs". Then, while accelerating, it straightens out...no problems. Until it shifts into overdrive, then it feels like I'm running over rumble strips.

I thought it may be a torque converter lock-up issue and I took it to a shop to get checked out. They told me my number 3 cylinder has low compression (80psi) and I need a whole new engine. They said the chug was due to the car not running on all six cylinders. I have no other symptoms of something wrong with the engine...doesn't use a discern able amount of oil, no coolant in oil, doesn't run hot.

So, curious what everyone else has experienced and if these symptoms are consistent with low compression on one cylinder. Thanks! By the way 181K miles, driven episodically as a second car by me and the previous owner.

YoshiMan

I had a goofy issue like this once. The engine ran fine when it was cold, but then would get all sorts of goofy once it warmed up, and idled terribly.

My issue was one of the vacuum switching valves on the back of the engine had one of the "nipples" break off, so once it warmed up, the valve would open and create a sizable vacuum leak. It's in a hard to see place, but you might be able to see it with a mirror and flashlight.

Jbinman

Cool, I'll check it out...I hear these motors have tons of vacuum issues. The shop I used did a horrible job. I got it back and they hadn't even checked the trans fluid level during their "inspection".

Trooper6

my 91 4runner is doing the same thing. the #1 cylinder has little pressure. to rebuild the heads would just cause it to burn oil and a remanufactured engine would be pretty costly. not sure what Im going to do yet, anyone got a suggestion?