97 Missing At Idle - HELP - Toyota Nation Forum : Toyota Car and Truck Forums

97 Avalon · 11-05-2008, 05:58 PM

My 97 Avalon is missing while at idle, but seems to be fine when I'm driving. I already ran seafoam through the manifold twice, so I can scratch that off the list of things to try. The plug wires and spark plugs are in good shape.

I also tested the primary resistance on the coils and that was within spec. It's pulling 21 inches of vacuum at idle so it doesn't seem to be a vacuum leak issue. The EGR is holding vacuum and that all tested fine with the vacuum pump.

Any other suggestions? It's getting annoying.

***new echo owner*** · 11-05-2008, 08:20 PM

Why do you think it is missing at idle? Does it have a CEL? Any code?

N.E.O.

97 Avalon · 11-05-2008, 08:30 PM

There's no CEL. I cleaned the MAF and the IAC as best I could just now and that seemed to help. I still hear a slight miss, but it's much less pronounced and smoother.

***new echo owner*** · 11-05-2008, 08:36 PM

If the engine is misfiring, there would be a CEL. Are you trying to fix an engine vibration problem at idle? How many miles on the car?

BTW, what do you mean by hearing a slight miss?

N.E.O.

97 Avalon · 11-05-2008, 08:51 PM

190,000 miles. I can hear what sounds like a slight lope coming from the exhaust, but it may just be due to the age of the engine.

It's smoother now that the IAC and MAF have been somewhat cleaned. I'll probably just live with it for a while. I need to get the timing belt replaced in 10,000 miles anyway so I can always have the dealer check it out when it's in there for that.

***new echo owner*** · 11-05-2008, 08:58 PM

Have you hook up a tach to see if the rpm is surging up and down? If the changes in rpm is less than 50, I wouldn't worry about it.

Did you run the Seafoam through the fuel system or just the intake? Restricted injectors can cause idle surge too, if you haven't maybe put some Seafoam in the gas tank and let it clean the injectors too.

N.E.O.

97 Avalon · 11-05-2008, 09:37 PM

Yeah I've run Seafoam through the brake booster vacuum line as well as the gas tank. I may run another can through the gas tank just for kicks.

***new echo owner*** · 11-05-2008, 09:43 PM

AS I had mentioned, if there is less then 50 rpm changes shown with a tach, you probably don't have any problem. But it won't hurt running the stuff through. So unless the CEL pops up, don't worry about an engine miss.

N.E.O.