I also have a 98 E320 that has p0170 and p0173. Similarly it bogs when you try
to quickly accelerate. Does not appear to be a vacuum leak. Check engine has
been on for 3 months or so. Sound like the MAF meter?
My defective air mass meter did produce trouble codes of P0170 and P0173,
but it did NOT cause any stumble or bog down in acceleration. Since my
engine appeared to be operating normally, I was able to compute the
developed horsepower at high RPMs under load from the measured air flow and
compare this to what I thought it should be based on the published
horsepower for this engine. That calculation gave me some confidence that
the air mass meter was defective.
However, one of the gurus on this newsgroup said that a defective air mass
meter usually causes a stumble on acceleration. Maybe it depends on how
the air mass meter is defective. In my case, the air mass meter was
producing an output which was about one half of what it should be in terms
of the cubic feet per minute of air flow. Perhaps if the air mass meter is
producing zero output or if it is indicating a larger than actual air flow,
a stumble on acceleration would result. I just don't know.
engine has been on for 3 months or so. Sound like the MAF meter?
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