mtnjam

1998 Toyota Tacoma 3.4L V6 5VZ-FE with 186500 miles on it.

I have some questions about what is going on here. This mostly started last week while coming home from a Thanksgiving trip. I started the vehicle in the lot at a ski area (not too cold ~25 degrees) let the vehicle warm up and drove back down the hill. No check engine light or anything like that. I got back to the house we were staying at, changed clothes, etc. went back out to restart the vehicle which had been sitting no more than 15 minutes and it started rough with seemingly low idle and idled very rough. Started the drive back home and although running rough still ran fine. I drove a ways and the check engine light came on, very rough running at ~50 mph under acceleration. The funny thing is that after a while the engine felt like it lost power and then regained power and the check engine light went back off. It stayed off until I stopped for a snack/rest stop. I restarted the warm engine and it ran rough again and the CEL came back on.

Took it to the shop the next day, they got some error codes on it, random misfires and some non companion? cylinder misfires. They replaced the spark plug cables and it ran fine again, from a cold start.

The other night I was driving back from the grocery store, same thing running rough from startup with warm engine and all of a sudden she just died, no warning, oil pressure light came on. She restarted, but still ran rough, got home, checked the oil, it was fine.

I start the engine in the morning and it runs fine, warms up properly, exhaust smells/sounds fine and the engine sounds fine. I stop, turn the engine off, run into a ski shop and restart the engine while warm and it starts to act up again, rough start and rough idle. The exhaust sounds like it is puffing, chugging almost.

Maybe somebody can help me figure out what is going on with this and why it starts fine when cold (although with a somewhat high cold idle) warms up fine and then while still warm after the engine has been off for a little while it starts rough. I do know it is kind of high mileage on this engine but I'd like to get it through one more season.

Thanks for any info.

rworegon

Post up the specific CEL code(s) the next time they pop up?
Condition of spark plugs? How does the oil and coolant look? Are you using coolant?
When was the timing belt last done?

mtnjam

I'll have to check the plugs, but the oil and coolant look fine. Not bubbles or watery oil on the dipstick. I had the timing belt and water pump replaced about 3 months ago. Not using coolant anymore staying pretty steady when hot and cold, but prior to that had some coolant leak around the water pump seals.

I'll post up the codes next time I can get them.

Thanks.

rworegon

Also, search cleaning the IAC valve and the MAF.

J2F42C

As rw said, pull the code and go from there. Such is paramount.

Follow his advice. I would also look to make sure the ground wire by the Diagnostic box is tight to the manifold. Also check the cam sensor connection on the front of the timing cover.

Last, make sure that crank bolt is tightened to 217ft/lb and no less.

vital22re

iTrader: (2)

I had a budy go through an ignitor on a 3.4 swap on his runner. It would run fine cold then as it warmed up it would stumble and die. We replaced the ignitor with a known good one and no problems.