Automotive Forums

1998 Toyota 4Runner Limited, original owner.

My 4Runner problem had 3 symptoms more or less concurrently:

1. Engine is running "loud" or rough constantly, at all speeds.
  The problem does not seem to affect acceleration or gas mileage.

2. The Check Engine light came on -- code turned out to be accelerator sensor.  Got it fixed.
  There were no other codes.  Mechanic notes that engine is slightly low on oil.
  Never had an oil problem before (have used Mobil One since the 4Runner was new).

3. After getting accelerator sensor fixed, engine still runs loud, but not quite
   in the same way.
  And the check engine light is staying off.
  Engine appears to have lost 1/2 to 1 quart of oil over 700 miles since the repair.
 
What could be the cause of the loud engine?  It sounds a little like the either the engine
is straining or the transmission is messed up somehow.  The transmission seems to have
a rougher feel to it.   But if it were a transmission problem, wouldn't it show up in
the computer check?

I'm the original owner.  The car is 9 years old and has had very little work done on it.
I've replaced the battery, and for the most part done the Toyota recommended
maintenance, timing belt, etc. that's about it.  

Any suggestions would be appreciated.