2000 Mk4 Limp mode/low power - Need help fast! Detailed description.

[kingalbrect79]

OK, so I've been through the ringer the last few weeks doing basic tune-up and maintenance on the car and now I've got a new problem.

I have a 2000 Jetta, 2.0 5spd.

A couple weeks ago the original water pump impeller broke so I figured it was time to do a tune-up.

So far in the last two weeks I've put in the following new parts:

Water Pump
Tensioner
Timing Belt
NGK Plugs
Plug Wires
Fuel Filter
Air Filter

All of these parts were purchased from a local VW dealer.

A couple days ago the car lost all power on acceleration and began to shudder at close to 3,000 rpm. When starting up it will idle fine, have good throttle response most of the time, although if you rev it enough it will sputter.

I researched it and talked with my guy at the dealer and he said that the MAF sensor could be going bad, or the coil pack.

So far I've done the following:

*Checked all vacuum lines (to which i could find no evident cracks, holes or rub marks)

*Replaced the MAF sensor with another one I got from my buddy at the dealer (I also checked the car by running it with it unplugged and it ran a bit worse, so the sensor checked out)

*Sprayed the coil pack with water while it was running to check for misses, arcs or if the car would die, no change, no sputter, no effect. Coil pack doesn't appear to have cracks (although it could still be faulty)

---------------------------------------------------

Other misc. info:

*The car does have an exhaust leak at the base of the pipe and the weld at the muffler (after the CAT). However I think another leak might have developed close to the car that is rattling that I can't seem to track down.

*The second bank O2 sensor is bad. It has been bad for several months, we've just not had the money to replace it as of yet. (we had the parts for the tune-up, just had not had time to do it yet as I was working on repairing a transmission for another truck of ours)

*For most of the winter the car has only blown luke warm to cold air through the heater even at full blast and when driving at operating temperature. Most likely this has nothing to do with the performance of the car, but it's worth noting anyway just in case. [Tested the hoses at the firewall and I think the heater core is plugged because the outlet hose is hardly warm and the lower radiator hose is ice cold even at 190 degrees normal operating temp.]

*I scanned the car for codes and came up with the following:

1. P1128 - Fuel Lean? This code I had to look up and from what I can tell it reports a lean condition in the motor although I'm not sure on the specifics of this code and how accurate it is.
2. P0301 - Cylinder #1 Misfire [This is most likely the reason for limp mode]
3. P0134 - O2 CKT No activity
4. P0135 - O2 Heater Circuit Malfuntion
5. P1255 - Fuel/Air Metering ? [I believe this was the code directly referring to the MAF sensor]
6. P0137 - Bank 1 Sensor 2 Low Voltage [Referring to the bad O2 sensor behind the CAT]

----------------------------------------------------------------

Other things I've tried:

*Running the car with the MAF housing unhooked from the Air Box to check for a plugged snorkel pipe.

I had added a can of SeaFoam to the tank just last night when we filled up to work on breaking down any potential carbon buildup in the fuel system, however the only other thing I can think to check are the injectors themselves.

I was considering pulling the injectors out and soaking them to make sure they are not plugged up. Other than that, I'm at a bit of a loss as to why the car is still in limp mode.

Any ideas would be greatly helpful and fast, as i've already lost a few days from work over this car {because it's been raining non-stop and I still need to put the trans back in my truck - I work outside...no shop}

I can't afford to lose any more days off from work. I've borrowed a vehicle for the next two days to try and iron out the issues with the jetta, but I need to have it fixed by the end of the weekend or I might have to start looking for another job.

Help?