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Airflow meter/regulator

My 99 Isuzu Rodeo has an issue. I have had it since it was brand new, and think I have babied it mechanically, however it does have 150,000 miles on it. Now I have a problem my mechanic is befuddled with (he’s great btw) and when I suggested i call C n C he thought that was brilliant. So in the past 6 months I have had to replace the air flow meter (regulator) three times. One my mechanic did it, then I took it to the dealership (desperation mode I know and they charged me an arm & leg) then a good ole boy mechanic at the NC beach over 4th July weekend as I was stranded. Connie’s BP at the beach was also awesome. Now the check engine light has come on again and once again my car is roaring and has all the symptoms of “needing a new Air flow meter”.

HELP! My regular mechanic Jamie is at a loss as to how to fix.

Now the check engine light has come on again Get the real code, it should be in the format [P1234] and post that code back here.

Okay, got the code today from Jamie and it is PO 101, same as before, starting to run like crap and the latest MAF meter installed July 5…what next?

A MAF sensor may be signalled as operating out of range due to an actual air leak in the intake, downstream of the sensor. You may have a loose intake manifold, a bad intake manifold gasket, an air leak from a positive crankcase ventillation hose or pressure control diaphragm between the crankcase and the intake manifold (that’s very common; either a hose is leaking or the pcv diaphragm/valve is cracked, causing air to pulse to and from the crankcase and the intake manifold).

Typically (though I do not specifically know Isuzu engines), once a fault code for the MAF is set, the engine control module would subsequently disregard the MAF signals and instead adopt a default air mass profile. From there, on, the engine would again run smoothly, not rough or surging as yours is. Your car seems to have all the symptoms of an actual air mass problem - which would be very understandable at 150k miles - and not a MAF sensor problem.

Codes can’t tell you that parts are bad. They refer to systems. The P0101 code can be set for a very large number of reasons. You need a mechanic who is a diagnostician rather than a changer of parts.

See this for general info:

Replacing a MAF 3 times is nothing more than wild guessin’ and prayin’.
What someone should do is examine, very carefully, the intake tract between the throttle body and the air filter for any signs of an air leak no matter how small and unobtrusive it is.

I ran across a MAF problem (alleged MAF problem) recently and it was not the MAF at all. It was a razor cut type split in a breather hose in which the hose had softened with age and oil. Under moderate to hard acceleration the hose would collapse and the split would open up a little. Ten minutes and 3" of spare hose later this glitch was solved.

You might define the “roaring” part of this. Foot on the floor, bucking and jerking, or what?
And what codes were present, if any? (The example I mentioned above; no codes at all.)

YES! Yesterday i noticed it was “rockin” when stopped at a light–like every 10 seconds I was imagining it was a horse that shifted its weight from left to right side. Plus it seems to be getting too much gas so like I have my foot on peddle ever so slightly.

Good luck! Let us know where you find the leak.