93 Camry 4 cylinder, auto. Engine has a random miss that comes, and goes.
 

I just bought this car back in Jan, and its had a little bit of miss, or stumbling that comes, and goes.

The car only has 95k miles, and is in great shape. First thing I did was change the timing belt, thermostat, waterpump, belt tensioner, change oil, and clean the idle control valve .

The engine will do this always about a mile from my house at the same exact spot in the road, then at random times even when the engine is warmed up.

The plugs are fine, and it looks as though someone did a tune up on the car before I got it.

So far there is no CEL. As of yet I haven't changed the fuel filter, but I don't think its related.

Also, there are no vacuum leaks as far as could tell testing with a propane tester.

Random in how?

Runs OK or stumbles when warm, cold, uphill, down, etc?

What's happening at that "exact spot" on the road? Uphill, curve, etc?

Going down a big hill it would surge/off/on/off/on, for around four seconds, and at red lights.

After posting this I went outside, and took the dist cap off, and sanded the contacts that connect to the plug wires [inside the cap, not the exterior yet, but maybe tomorrow].

Then added dielectric grease on the rotor, and contacts.

Strangely enough it seems like that cured it.

I do plan to also lightly sand the outside plug wire terminals on the cap, and add some dielectric grease there as well.

Being a mechanic for over 35 years now, its rare that it was such a simple fix.......lol.

Great job! Thanks for posting back.

The IAC valve control engine idle. Try cleaning the valve.