Anyone know their Audi/VW 30V V6s?

[DieselPaul]

I have a 1999 Passat 30V now. It idles kind of rough and if you rev it to say 1,500rpms and hold it, it will buck up and down like 2-300 rpms. When you drive it it will buck a under load and if you go full throttle you don't get much power.

The car is throwing a P1545 code, which I understand to involve the throttle body.

I tried the door open hood open TB reset thing, I didn't hear the TB doing anything.

The car will free rev up, but once you get near 3k it sounds kind of sick and I didn't want to wind the crap out of it not knowing the problem .

I have an OTC scan tool, so not VAG-com or anything good, its a really nice scanner... from 1999 but it will do Generic OBDII, my TPS is reading 0.00% all the time. Is it possible my TB is messed up or something? When in drive and driving 10% and 100% throttle (guessing on my foot position, scanner always shows 0%) the car will accelerate the same and doesn't seem to want to rev above 2k and go much faster. It does shift into second though.

Another possible issue, once when the car was idling it randomly went from showing 190* on the gauge to showing zero. And then today my scanner at one point showed a ECT (engine coolant temp) number of -40*, I unplugged my scanner and tried and again it showed 190-192* and the gauge showed the right thing from then on. Didn't know if maybe a coolant temp sensor could keep the car in some rich warm up mode.

I DID replace the valve cover gaskets, they were dribbling, I was told to hope the spark plug tubes were leaking and that could fix it but, they were fine. I pulled the plugs, they looked a little rich, but not worn at all. They were NGKs, so someone replaced them.

Someone redid the vacuum lines on the top of the motor though, the car has 115k, I was told it was replaced at some point. Is there a 2.8 30V vacuum diagram so I can make sure that it is all routed correctly?

Thanks!

Side notes, the car does not run hot, does not blow white/blue/black smoke, etc. Something is just messed up, its not like the motor is just wiped out or something.

[AdvisorGuy]

Sounds like the TPS so I believe it's replacing the throttle body. Coolant temp sensors are common and usually cause the guage to go flat. It's located in the pipe that runs behind the intake..

[DieselPaul]

Temp sensor is $11 new, I'll order one soon. I'm thinking about just buying a used throttle body for $70 with a 6 month warranty versus $560 for a new one haha

[AdvisorGuy]

Originally Posted by DieselPaul

Temp sensor is $11 new, I'll order one soon. I'm thinking about just buying a used throttle body for $70 with a 6 month warranty versus $560 for a new one haha

I meant to come back & suggest that. If I recall correctly, it's pretty much just a horseshoe type clip that holds the temp sensor in place. TRUST ME, replace it with the engine ICE COLD. Also, don't bother draining the cooling system. If you just leave the cap on the reservoir, your coolant loss will be minimal. If the system hasn't been flushed in some time, do it before the heater core clogs, Seen that too many times with VAG products and the whiz-bang G-12 coolant...

[Pooka]

Pay attention to the heater core advice. I have changed these on Audi 5000's and 100's. after they went bad.

No fun at all.

[DieselPaul]

Someone put green in it, I plan on doing a flush to get that out and get G12 back in it.

I was going to buy the sensor, clip, and oring from ******** for like $11-12

I am going to try to clean the TB first but $70 to replace isn't too bad if it will fix the car.

[AdvisorGuy]

Originally Posted by DieselPaul

Someone put green in it, I plan on doing a flush to get that out and get G12 back in it.

I was going to buy the sensor, clip, and oring from ******** for like $11-12

I am going to try to clean the TB first but $70 to replace isn't too bad if it will fix the car.

GREEN !!! OIE VEY lol.. Green & G 12 mixed or not completely flushed before green was installed... I can feel that heater core restricted like a clogged artery. Allow me my long-winded advice

Since you're gonna be back there doing the temp sensor and you are gonna flush the system, pull the hoses that go to the heater core after you drain it and try to look inside. You may very well see Chunk-O'-Coolant in it. If it looks in the least bit restricted, pour some flush directly into it & let it sit - you may want to get 2 bottles of a heavy duty flush. Flush the heater core on it's own a time or two. Then take the two heater core hoses and loop them together with a piece of pipe, flush tee, etc, as to separate the core from the cooling system loop. Flush the cooling system on it's own. I say get 2 bottles because it just may be like directions on a shampoo bottle - lather/rinse/repeat if the core is in the least bit clogged. Once all flushed out, reconnect the core hoses to refill the system. Do know that they're sometimes a real PITA to bleed the air out of the system so be patient.

I've seen many a B5 / B5.5 chassis Passat & A4 in particular, need heater core replacement due to "no heat." Flush the cooling system every 2-3 years..