I have a problem with my 95 3.0 runner. It has been losing power at random times. It will go away and I cant go over 40 mph. then it will just come back like instanly like somebody hit a shot of nitrous (not that fast though its a 3.0). It will then go away again. It not like its fading in and out. its an INSTANT lost or gain of power. Any clues where to start looking.

 

check your fuel filter and injectors...do you have a CEL?

 

Fuel filter is less than a year old. No CEL

I forgot to add an important part. Engine runs perfectly at full throttle. I actually can out run a friends runner of the same year just the way it is. its anything less than 3/4 throttle im having problems with. Also if I let it idle for more than 2 or 3 minutes it will load up ,start loping and die unless I rev it to clean it out. It smell horrible rich at idle and is getting about 9mpg

 

o2 sensor

 

I was thinking o2 also, but its such an instant loss and gain of power that it almost seems like something is shorting out. It "feels" like when you try to go, its lean and bogging then suddenly it gets fuel and takes off.

It seems to take off fine and loses the power about half way through second gear. If I let off the throttle fully, and then hit it again its got power for about 3 seconds but then drops away again and wont come back unless i floor it or let of f and hit it again. If it were the VAM or TPS O2 or KS wouldnt they set off the CEL? Power never falls off at WOT. only less than 3/4. So I think that counts out a clogged cat, injectors, or fuel filter, or bad fuel pump. If any of these were bad it would have problems at WOT. Right?

 

a o2 sensor can fail and not show a cel also climb under there and make sure its pluged in tight

 

Is there anywhere on the 95 to attach a FP gauge? I have looked along the fuel rails and lines and dont see a port anywhere.

 

If you can't go over 40 I would say it's a bad fuel pump

 

It sounds like a possible sticking AFM to me. Look for cracks in the intake hoses between the afm and t-body too.

 

I'd say o2 sensor or fuel pump, my 2cents.

 

Ok, yestday I was idling at a stop light and it started to act up on me. I tried to go and it would barely move. I pulled over and the idle was surging up and down from 500 to 1200 RPM. I had temporarily popped the top off the AFM so I could see if it was sticking when it started acting up. I sloooowly closed the AFM a little and it got worse. I let go and it went back to surging. I sloooowly opened the AFM a little and it started to idle perfect. I let go and it back to surging. I opened it a few more times and it ran perfect everytime. So my problem is that its going lean but I still dont know why. Could it be that the AFM is shorting out or something and not reading consistently? If its shorting out it would explain the abrupt gain or loss in power.

It literally can go from barley running to running perfect in the blink of an eye. This I think point to a sensor or some sort of short in something. I think the fact that it will run perfect half the time rules out anything like fuel pump, filter, injectors. Also the fact that it runs great at WOT tells me these parts are fine as well. If any of them were bad, the problem would still be there at WOT cause it would not get enough fuel.

 

Classic TPS symptoms