What I should have said is, "that in my experience", it has always been due to a lean condition.

The message I was trying to get accross is..... do the obvious stuff first.

ie... If the car hasn't been tuned up in a while and it runs like crap, a good place to start would be to tune it up.

A fuel filter is a small price to pay for something that "could" realistically fix this problem.

Please remember, I'm only trying to help.