loping idle fixed with Techron?!

[murphymp]

I've got a 94 camry 4cyl auto with 230K miles. It's had a loping idle after the car is warmed up. Basically what happens is when you're stopped with the car in gear and your foot on the brake, the RPMs will start to fall and then will pop back up. The problem is intermittent and the loping is random but it's getting worse with the warmer weather. The car stalled when backing out of a parking spot a couple of days ago.

I've cleaned throttle body, IACV, new plugs, and have checked for vaccum leaks. When I ran a container of Chevron Techron through the gas, the problem went away. Unfortunately, it came back when I had to put a new tank of gas in. I've added another round of Techron and it's running fine right now. I suspect the problem will come back when this tank of gas is burned up. What does this indicate? I don't really want to spend $9 a fillup for a container of Techron every time I buy gas.

Any comments/suggestions appreciated.

[islandboy57]

My gf's old Legend had/has the same problem. First replacing the IAC valve fixed it. Now, I think the alternator is on its way out because you can see the lights dimming when the RPMs dip every other second. She's trashing the car because it needs $2-3K in work. But yeah, man is it annoying to stall while you're reversing!

[Axxis8203]

the techron is probably boosting your octane rating, try the next grade up of gas next time you fill up and see where that goes.

[ASG14]

Try putting SeaFaom through the brake booster line. May help.

[murphymp]

Thanks. I forgot to mention I've already seafoamed it twice. The wife thinks the idle improved "somewhat" after that, but I'm not sure.