I need power...

[4zstracker]

Hi just wonering if anyone can help me with a problem that im having with my Geo Tracker. I posted about this problem before, but things got all crazy for me and i pushed it off to the side. But the problem sure dint go away, darn things.
My Tracker is a 1996, 2 door, 4x4, 5 speed, it has the 1.6 L, 16 valve, with MPI. Ive only owned it for about 5 months now.
This is what is going on: It has no power at all, it acts like its running super lean. It wont start and run cold, and if it does start it will idle between 100-300 rpm. Once it gets warm it will only idle at around 500rpm. But heres where it get kinda wierd, if you get it warm and running, and you mash down on the go pedal it bogs down, and will actually die if you dont let up. So to get it to rev up you have to just barely touch the throttle until it gets to about 2000 rpm, then you can get on it a little bit more, but again, if you really get on it it will bog down. It also has absoloutly no power at all, you actually have to feather the clutch at about 2500 rpm to even get it to move without bogging and almost dying. At first it was just an intermittant problem, that just got progressively worse, but over the last 2 months it has become a very serious driveability issue. At this point it is so bad that i can no longer drive it.
It has gotten really frustrating trying to figure out what the problem is. At first when this all started i thought that it just needed a tune-up. So i did a full tune-up, plugs, wires, cap & rotor, oil change, air filter, fuel filter, the fuel pump was failing so i replaced that too, it also has a brand new TPS, it was showing a code for that so it got replaced.
Mechanics have been no help at all. One ASE certified tech told me that it was a fuel injector problem, so i checked them, no problem there. Another guy told me that it was the fuel pump, so I checked that, it was going bad so i replaced it, no change. When i pulled the codes it showed a bad TPS, and a random misfire. So i put in a new TPS, today actually, and it didnt help at all. I have also removed my intake manifold and cleaned it. Ive cleaned the entire EGR system with no results. I have also done a compression check to see if my valves and rings are okay, and all of the cylinders compress just fine.

After all that i would like to think that it should run a ton better, but it just gets worse and worse. Could it be the ECU? Is it in "Limp Home Mode" or something? Would the computer keep it doing that until you clear that code, or is that just a one ignition cycle thing? What else could it be? The fuel pressure regulator maybe? im about at the end of my rope here. Thanks in advance for any help with this.

[Markb873]

That's a tough one! Hook up a fuel pressure guage and tape it to the windshield. Drive it around and monitor the pressure, then you will know what action creates how much of a drop in pressure if any. However, I haven't had a Tracker in a few years, I don't remember if there is a hook up on the fuel rail for a screw in fuel pressure guage.

Also have you checked your valve timing? I had a vehicle that had a bad case of progressive timing slippage, and the timing would slowly retard.

Long shot but, I had a beehive in a muffler once when a car sat for a few months, it gave the same symptoms, I wonder if there could be a restriction in the exhaust. Plugged catalyst maybe?

Good luck
-Mark

[coopdavillage]

yeah sounds like it might be a plugged cat, you can also try the O2 sensors they will cause somewhat of the same problem. had an 84 crx that had a clogged cat though and i couldnt even get over 30 going downhill in california. ended up stuck at a mechanics in sacremento and had to punch it out to even get it to start up. good luck and hope you figure it out