Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

2002 svt focus high,lean idle

when I plug in my brand new and original mafs my engine idle roars up to a constant 4k and my headers glow orange?

How can your mass air flow sensor be “brand new” and “original” at the same time?

I believe he is saying he has a new one…and his original one now. You should honestly Never unplug and replug in your MAF while the engine is running. Is this what you are doing or are you shutting it down first.

What symptom did you have that made you suspect the MAF ? A little more background info would be helpful…we are only as accurate as the problem description here in internet land.


It sort of sounds like you may have a big air leak somewhere, that is allowing unmetered air into the engine. Check for broken rubber boots, etc. A faulty brake booster could do this too. Even a faulty pcv valve. Anything that connects to the intake manifold is suspect.

I’m guessing he either had a P0101 or P0174

I plan on removing the intake manifold this weekend to check for cracks. It’s plastic and I think your right about the air leak. SVT uses a idle air control valve since it’s a cable throttle. I unpluged it,plugged it the mafs and the rpm still shot up. My code reader detected the iac open. It’s got to be a crack in that plastic intake. I did change the brake booster last weekend with no positive results as far as the high idle goes.Thanks for the help!

They LOVE to come unglued…and or crack.

yes, that’s got to be it. thanks!

My vote is for a large air leak as well.

I bought some JB weld.

How about a proper diagnosis?

So far all I hear is assumptions, which often leads to unnecessary and expensive parts being thrown at a car, possibly without actually solving the underlying problem

seen it lots of times

I agree…these are all just theories…possibilities for sure. Personally I have tons of theories whenever I am facing a diagnosis…my job is to properly prove them out…then buy the right parts… I expect the same of others…but maybe Im asking too much?