If anyone can help with my TT problem I would be AMAZED

[csf]

I have a 2000 1.8 TT that just does not want to run properly. I am getting pretty consistent misfire and a severe loss of power. The misfire is worse when the ac is running. Here's what I've done: Replaced all plugs and coils Replaced fuel filter and fuel line New Catalytic Converter New O2 Sensors Cleaned MAF Replaced Coolant temp sensor Replaced Air intake temp sensor New Air Filter New Thermostat New Coolant Run Several Fuel System Cleaners through gas Tried premium gas from several different stations Checked for vaccum leaks by blowing smoke in lines and spraying hoses with carb cleaner That's about as much as I can remember at the moment... Long story short, it runs horribly. The car was way down on oil and I topped it off...oddly enough after I did this it seemed to run much better...for about 15 minutes and then misfire...sluggish. Right back to it's old self. Also, we check compression. All cylinders are around 200-205. Their is a hose that is leaking some coolant on the drivers side of the engine out of the block area, under where the coolant temp sensor is. Here are the things I am considering trying: New EGR valve New MAF New Timing Belt New Alternator and or Battery The car isn't throwing any codes other than the occasional misfire code. Even though I was down more than a quart of oil it never showed the oil light. Anyway...I am pretty much running out of ideas. Why the worse misfire when the ac is on? Why did it run almost perfectly with some new oil? If anyone out their can help me they are superior to the dealership who were unable to help...so, any ideas?

[Jdaniel343]

This might help

Originally Posted by csf

I have a 2000 1.8 TT that just does not want to run properly.

I am getting pretty consistent misfire and a severe loss of power. The misfire is worse when the ac is running.

Here's what I've done:

• Replaced all plugs and coils
• Replaced fuel filter and fuel line
• New Catalytic Converter
• New O2 Sensors
• Cleaned MAF
• Replaced Coolant temp sensor
• Replaced Air intake temp sensor
• New Air Filter
• New Thermostat
• New Coolant
• Run Several Fuel System Cleaners through gas
• Tried premium gas from several different stations
• Checked for vaccum leaks by blowing smoke in lines and spraying hoses with carb cleaner

That's about as much as I can remember at the moment...

Long story short, it runs horribly. The car was way down on oil and I topped it off...oddly enough after I did this it seemed to run much better...for about 15 minutes and then misfire...sluggish. Right back to it's old self.

Also, we check compression. All cylinders are around 200-205. Their is a hose that is leaking some coolant on the drivers side of the engine out of the block area, under where the coolant temp sensor is.

Here are the things I am considering trying:

• New EGR valve
• New MAF
• New Timing Belt
• New Alternator and or Battery

The car isn't throwing any codes other than the occasional misfire code. Even though I was down more than a quart of oil it never showed the oil light.

Anyway...I am pretty much running out of ideas.

Why the worse misfire when the ac is on? Why did it run almost perfectly with some new oil? If anyone out their can help me they are superior to the dealership who were unable to help...so, any ideas?

[J. Patterson]

Low Oil---- Misfires ------
Could be in d=need of a pcv system rebuild

You really cant check for boost leaks without using pressure.

http://http://www.youtube.com/watch?v=Gup5IsypU_8

[Jpollock]

Maybe an injector? .... Everything either goes to or gets created by the ECU....AC being on almost definitely affects timing....

I've had decent luck with my 01 except for my current fuel issue .... And so far everything has been an electrical connector issue. If I had listened to the dealer ech time, I would be $3000 poorer.

Back window intermittent theyvwanted to replace for $1200-$1500...I cleaned the connector and it's still working.

A draining battery I had in several times and they finally said I need a new ECU...nope it took a while but I tracked down a couple of wires in a connector touching ever so slightly poorly manufactured..

So I tend to cleaned connectors first ...

Good luck

[Prospeeder]

I think it sounds like something crankcase ventilation related. Like PCV components collapsed, clogged, or the vent valve stuck open.

[TimeOrMoney]

Need to check the fuel pump pressure, and then the injectors.

There is only electrical(spark, timing), air, or gas. Sounds like electrical has been covered, and air doesn't seem like it would be what you are seeing, so .... gas!

Oh, there are transistors that fire the coils, but when it happened to me on a different 1.8T, it was total, like one cylinder is totally not working. I think that's the normal failure mode. You'd know if you had this though; it's dramatic when you lose one cylinder on a 4 banger!