Nissan Altima: 99 altima slipping

When the A/C is on the Computer that controls the engine will take some
steps to ensure that the extra load from the A/C compressor does not stall
the engine. This consists of adding a little more rev to the engine, on
the order of 200 RPM, this can be seen best at idle. When you take the car
to the mechanics, tell them the problem, and let them figure out where it
is. Let them do thier job, they may know something right away, but it's
best you let them start from your description of the problem.

If the transmission shifts fine with the A/C off, then the problem will
not be anything in the transmission, mechanically at least.

Possible problems could be a faulty Idle Air Control Motor (goes by
several names IAC, EACV, ISM), ECCS (ECM) failure, or maybe a motor/tranny
mount. If the mount is too loose then the motor could be moving too much
when the A/C demand kicks in, and the shifter cable could be getting
pulled causing unexpected changes gear selection.

thanks for the reply MegAltima, it turns out though that it is the timing
chain - mechanic said that the timing was off by 20%. He said he cranked
it over as far as it would go (19%), but says that this will most likely
continue to get worse. I just can't believe something like this could
happen literally overnight - 20% is a long stretch. They quoted a new
chain installed for $1500US - does that sound right? - any idea how this
could happen? - is there anything i can do to help prevent this from
getting worse? - thanx for your help

"spiccolli" <com> wrote in message
news:talkaboutautos.com... 

That price sounds about right with labor charges, if you have a friend or
can do it yoruself though should be much cheaper. But if you dont have exp
I wouldnt tackle this.