Five04sho

I have a 93 Ford Festiva. I have replaced the fuel filter so far, but still have no idea whats going on. It starts up and runs just fine, but when I drive it I am only able to put the gas pedal down a quarter of the way. Anything more than that it wants to cut out. When i let off the pedal a bit I feel the engine smooth out. But its just annoying only being able to take off at 1/4 throttle, and when going up hill i have to down shift because I cant give it enough gas to keep it up to speed with out it cutting out. Side notes: Like I said earlier the fuel filter has been changed. The owner before me removed the catalytic converter for some reason, and the exhaust has a huge leak back by the muffler...not sure if the lack of back pressure is causing the drop in power... codes that were read off it were 2 oxygen sensor codes and a "fuel system lean" code which I believe is making it smell like gas in the exhaust from the computer dumping more fuel, or it could be the lack of a catalytic converter... anyone have any ideas?

CatSkinner

The car has some years on it, are the O2 sensors original, or don't you know? It sounds like the sensors need to be replaced, which would explain the lean code as well as the O2 diagnostics. The lack in back pressure would only improve power, but you could have a plugged exhaust. Does it maintain a steady idle, or does it seem to hunt at times? The computer really controls fuel flow via vacuum regulation which is controlled by the throttle body... in a sense. I think the first thing I'd be doing is checking the vacuum lines and looking for potential leaks, get your O2 replaced if that's needed, and find out what your fuel rail pressure is.

__________________
Prius repellant, just add gas.

Bert

Can you make it do that in neutral. Try running this test, Fuel Injection Technical Library » How To Run a Self-Test and do a fuel volume test.

__________________
Bert

Five04sho

Yes it will do it in neutral also. If I slowly increase pressure on the pedal it will wind up, its when I try to put the pedal down quickly it wants to cut out. If I hold the throttle down it will choke itself out and die

Five04sho

And catskinner, I tested for vacuum leaks around all hoses by spaying starting fluid around them with the engine running, and the idle never picked up so I assume no vacuum leaks?