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2003 Ford Focus LX 4dr Sedan

2003 Ford Focus
Trim Info:
Front Wheel Drive, 4 Door Sedan, Compact
27 mpg city / 36 mpg hwy
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January 17, 2013, 5:56 am

John N

Question: IAC issues?

Over the last week or so, my car has occasionally started very roughly. It stumbles and is very rough. After about 20 or so seconds, it smooths and drives fine.

Also, I've noticed in the last few weeks that there is a noticeable drop in power when I turn on the blower, even with the AC off. Not a loss as where it stalls, but still very noticeable. Then I've also noticed that when I'm at a long light, or other times I start it and it doesn't stumble/start rough, that it will sort of feel as if someone is slowly pushing down on the accelerator and releasing, and this can go on for a while. Not dramatically, but definitely noticeable.

January 25, 2013, 3:37 pm

Ron W
Expert Mechanic

It is very possible that the IAC is the issue. And it is a common issue. You can try cleaning the throttle body (with throttle body cleaner available at most parts stores) as sometimes soot builds up and gums up the IAC circuit.

All this is assuming all the basic tune up items are done and the charging circuit is working correctly.

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January 29, 2013, 5:07 pm

John N

Thanks! I finally got a chance to clean the throttle body this weekend. There was a noticeable improvement in the idle for a couple days until this afternoon. Then it started to happen again and it threw a CEL (haven't had it checked yet). Should I also check for vacuum leaks?

About 3.5 years ago it had all sorts of issues in about 2 weeks, which lead to new wires and plugs, alternator and fuel pump. About 55k since then.


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January 29, 2013, 6:31 pm

Ron W
Expert Mechanic

If it helped, I'd suspect the IAC motor itself is sticking and it was temporary fixed by the cleaning. However, I wouldn't change just just yet.

55K and 3 1/2 years is definitely time for some tune up items. And I would start there as the that could be the whole issue. the ignition system may just be weak and need to be serviced.

If after that is done, you still have issues look at the IAC motor. And get the code pulled from the computer to make sure it isn't indicating something completely different.

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January 30, 2013, 5:58 am

John N

Thanks! I'll take care of the tune up items and then check about the IAC motor.

One thing I thought about last night that may or may not be interesting. Last Nov. I cleaned the battery terminals, and the next morning it seemed to idle a bit rough (nothing like lately) and I did throw a code. (sorry, can't remember). After about 2 days the CEL went off and it idled ok until recently.

0/0 users found this helpful.

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