I drive a 2002 Toyota Camry. Mostly runs great! If I drive on the freeway at 60-70 mph for 30-45 minutres, when I get off on surface streets the engine starts to die. I have to keep one foot on the brake and one foot on the accelaror to keep the engine >1000rpm. When I park at my destination and park the car for 1-2 hours, everything is fine whejn I start up again. Happens repeatedly - not always, maybe 95% of the time. Two mechanics can’t figure it out and are unable to reproduce the probelm after they drive the car on the freeway. Any ideas.
The problem might be with the Idle Air Control valve.
The IAC valve is what allows the engine to idle whenever the accelerator is released.
The fact that you’re able to prevent the engine from stalling while stopped by slightly stepping on the accelerator points to a faulty IAC valve.
Can you post the codes that the ECU had stored? I’m sure the mechanics must have checked them. Hopefully they wrote them on the shop orders.
If there were no codes at all, that too is a clue, as it helps eliminate some possible suspects.
Since it only happens when you come off of a highway run, I’d be inclined to suspect something becoming heat soaked, perhaps the cranks sensor or igniter.
Another, albeit longshot, possibility is that the gas tank isn’t allowing air to flow into the tank at eth rate it should as the gas is pumped out creating a vacuum in the tank that needs to dissipate to allow the pump to maintain proper pressure. That would be a saturated charcoal bed. This idea is, admittedly, a bit “out there”, but not impossible.
Any of these problems should store fault codes.
Is this a 4 or 6 cyl. The 4 cyl does not have an IAC the idle is controlled by the computer through the throttle by wire. When mine had idle problems a good throttle body cleaning solved the problem. If you do the throttle cleaning your self make sure the car is turned off (remove the key to be sure) because if you force the throttle plate open with the ignition on it will damage the throttle control motor and I hear it may be expensive.
Do you have a temp gauge or idiot light? If idiot light my guess a bad temp sensor and low coolant, or lack of coolant pressure.