Toyota Repair: help with a problem, toyota rav4, toyota dealer


Question
My friend has a 2000 Toyota Rav4 with a 4-cylinder engine, an automatic transmission, and a little over 61000 miles.  The engine is exhibiting some unusual behavior.

When the engine is in this unusual condition (which is not constant), it will not go past 4000 RPM, acceleration is very weak, and it wants to stall at idle, both in gear and in Park.  Again, this does not happen constantly, but it is definitely noticable when it does happen.

The engine sounds fine when it is operating normally, and there are no other indications that something is wrong.  I plan to replace the fuel filter to see if that helps.  If not, do you have any ideas what the problem may be?

Answer
Sounds like a restriction in either the intake or exhaust system, fuel filters normally don't clog up this soon, check the air filter first, then replace the fuel filter and see if it helps, there is also a possibility that the catalityc converter may be getting clogged and restricting exhaust flow, I would recommend having the toyota dealer check for this, the converter is covered for 8yrs/80,000 miles under the federal emission control warranty(if you live in the US).