I own a 1994 Toyota Camry V6 with 140,000kms (87,000 miles). I've had it around 9 months and it's purred like a kitten until very recently. I had a major service done to it around 2 months back when they replaced the air filter, fuel filter, oil change plus a couple new tyres.
I normally drive it with the overdrive on all the time.
In the last couple of weeks, I've noticed a problem. Firstly, it will intermittently idle quite roughly whilst paused at traffic lights. It doesn't do it every time, nor necessarily every day. It also does it whether or not the overdrive is on or not.
The other problem is that going at around 80-100km/h (50-65mph) up any form of incline, the engine appears to "cough", as though it is trying to drop back from top gear into the next gear, but something is preventing it from doing so. It only ever does it whilst going up an incline. As opposed to the intermittent rough idling, this other problem is now happening every single time I have the overdrive on whilst driving at that speed up an incline. It does not do it whilst I have the overdrive off. Thus, it makes me suspect there is a problem with the overdrive.
Anyone had this problem or know what the likely culprit may be?
If I were you, I would put some fuel injector cleaner in the tank and run a
few tanks of premium (93 octane) gasoline (petrol), to try and get rid of
the rough Idle. It could be a bad spark plug, distributor, or it may be
time for a new timing belt.
As far as the transmission problem, change the fluid, check your belts for wear and taughtness. If that does not fix your problem, it may be in the Automatic controller computer, the "brains" of your tranny.
If it is not an easy fix (i.e. requires a new timing belt and computer), dump the car. Sell it to an unsuspecting kid.