engine runs intermittently rough

[thilliard]

I have what seems to be a thermal related problem with the engine. The car is a 1999 Solara SLE with the V6 engine. It has about 93,000 miles on it. Normally the engine runs great but whenever it is driven over about 20 miles, the engine runs rough and appears to be missing. It does not do this in the Winter. I had the Oxygen sensor replaced at 90,000 and the timing belt at 50,000 miles. A few months ago, it started doing this on the freeway so I pulled it into the nearest Toyota garage and suggested they look at it right then while it was running rough. They agreed there was a problem and put it on their test equipment but could find nothing wrong except an idle sensor. They replaced that but it did not affect the problem.

Does anybody have any ideas what the problem might be?

[bronzemaxell]

Originally posted by thilliard
I have what seems to be a thermal related problem with the engine. The car is a 1999 Solara SLE with the V6 engine. It has about 93,000 miles on it. Normally the engine runs great but whenever it is driven over about 20 miles, the engine runs rough and appears to be missing. It does not do this in the Winter. I had the Oxygen sensor replaced at 90,000 and the timing belt at 50,000 miles. A few months ago, it started doing this on the freeway so I pulled it into the nearest Toyota garage and suggested they look at it right then while it was running rough. They agreed there was a problem and put it on their test equipment but could find nothing wrong except an idle sensor. They replaced that but it did not affect the problem.

Does anybody have any ideas what the problem might be?

mine (99 se v6 5sp) does the same thing, i could see the minor rpm fluctuation as well.
could it be a toyota defect?
i am thinking it might the throttle body or pvc needs some cleaning.

[chronoti]

Originally posted by bronzemaxell
i am thinking it might the throttle body or pvc needs some cleaning.

yup thats what i would say just get a can of carb cleaner and start cleaning or maybe change the fule filter, and clean the injetors

[thilliard]

i am thinking it might the throttle body or pvc needs some cleaning.

I checked my 90,000 service record and they did EFI and Throttle Body Service and added a "fuel additive". Any other ideas for the cause?

Tom