2000 GLS 2.0 Trouble Code Question

[huangt]

Thanks for the great forum. I just bought a used Jetta and it is already hesitating and bucking at high and low RPM. The problem seemed to be related to rain but recently it died completely and now runs with the check engine light. I pulled two codes

Trouble code
P0121 - Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem

Pending code
P0103 - Mass or Volume Air Flow Circuit High Input

Any clues on where I should start. I don't see much info in the parts list for a throttle position sensor. I have seen some discussion about coil packs related to hesitation but the codes say otherwise. Also, I have 60k miles on the car. Thanks

[huangt]

I have more info. I took the intake apart and it looks one of the breather lines spitting oil in the duct between the mass airflow sensor and the throttle body. I checked to see of the oil was overfilled and it is actually quite low. Thanks!

[Puffpuff]

Originally Posted by huangt

Thanks for the great forum. I just bought a used Jetta and it is already hesitating and bucking at high and low RPM. The problem seemed to be related to rain but recently it died completely and now runs with the check engine light. I pulled two codes

Trouble code
P0121 - Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem

Pending code
P0103 - Mass or Volume Air Flow Circuit High Input

Any clues on where I should start. I don't see much info in the parts list for a throttle position sensor. I have seen some discussion about coil packs related to hesitation but the codes say otherwise. Also, I have 60k miles on the car. Thanks

1996 vw jetta 3, 2.0 Huangt...., I got the same codes with my ride. In my case my car died during a rain storm. I poped my hood and carefuly checked around my coil....low and behold arching. I replaced it and my problem was fixed. I would bet money on it.

[Puffpuff]

Originally Posted by Puffpuff

1996 vw jetta 3, 2.0 Huangt...., I got the same codes with my ride. In my case my car died during a rain storm. I poped my hood and carefuly checked around my coil....low and behold arching. I replaced it and my problem was fixed. I would bet money on it.

Oh yeah. I got the oil in the intake hose too. It was inside the intake/TPS and by the EGR hose. I got the MAS sensor code and air temp sensor with mine.I replaced the MAS with a good used part. It worked for a while by has started to F up again. It has something to do with that oil. I just forgot about it.

I guess I better keep my day job.

PEACE

[bahnfire]

At 60k, the air screen inside your air box, below the air filter, may be clogged with dirt and blocking air flow into your engine. Cleaning out the air screen and replacing the air filter while your in the air box should increase your pickup, your mileage, and smooth out your engine’s idle. The purpose of the air screen is to keep small animals out of the air box; a common place for them to store food or build a nest.

When the mass air flow meter was replaced, the air box was probably vibrated enough to cause some of the dirt on the air screen to fall off and give temporary relief.

As far as the oil issue goes, I’d clean out the PCV valve in the breather leg with some carburetor cleaner followed by few hours in soapy water. The flapper inside may not be moving properly and the vacuum line connection on the valve may be clogged. If you notice some oil on the out side of the PCV valve, I’d seal where its coming from with a bead of high temperature silicone from your auto parts store. If you notice oil on the outside of the breather line at hose connection points, I buy a set of hose clamps and tighten the connections.

Coil packs can eventually crack in several spots from heat and vibration. The cracks allow moisture to get in and cause some cylinder banks to missfire in rainy weather. This is a common problem with many VWs and Audi's. The cheap fix is to remove the coil pack, clean it up, and apply high temperature plastic weld or epoxy along the crack lines. Let the sealant dry overnight and you should be good to go for a long time. You can get the plastic weld or expoxy at many automotive shops for less than $5.

Hope this helps.

[veedubmechanic]

Time for a new MAF sensor (about $80 at vw).

Time for a new throttle body ($250)