Ok guys, i need some expertise here. I've been posting in a VW forum (please forgive me) trying to figure out the root behind a problem with crap mileage and power in my moms VW.

We aren't getting anywhere, so I need the help of some experts

here is what has been discussed already (mine in green, response in red)

my 98 2.0 Cabrio has very little power, and isnt getting very good mileage.
I have done the regular maintenance, oil change, plugs, wires, cap, and I'm fairly mechanically inclined, however I can't figure out why this 2.0 is so weak.
I'm not getting smoke, or carbon soot out the exhaust. I'm not burning oil.
When i changed the plugs they appeared chalkl white which lead me to believe that she is running lean. I ran injector cleaner, and cleaned the MAF sensor, still no change.
What frustrates me most, is that I have a lot of power (haha for a stock 2.0 that is) when the engine is cold. I can spin the tires through first gear without dumping the clutch even, just mashing the gas. But as soon as the engine hits normal operating temps, its gutless.
Only after market part on the car is a higher flow drop-in filter

Is your check engine light on?
Could be the MAF sensor or coolant temp sensor.
Do you have rough idle or any off-idle drivability issues?
Poor gas mileage would suggest running rich.
When was the last time you changed the air filter? Could be a plugged catalytic converter. You can perform a quick vacuum gauge test to see if it's the cat. That or just remove the o2 sensor (and unplug it) to see if there's much change in performance

no check engine light, no warnings on my buddies diagnostic code reaqder.
The MAF sensor is clean. I don't know what the coolant temp sensor is, but I'll look into it.
I don't have a rough idle or issues driving.
If it was running rich I'd see soot out the exhaust, or fouled plugs, but i have chalky plugs, showing lean.
The air filter is almost brand new, and the old one wasn't very dirty. I just changed it anyways to reduce the variables.
I never thought of the cat. I will check soon.
What's bugging me most is why the enigne is stronger when its cold. As soon as it hits operating temp its crap

is your coolant flange leaking? If it is and the leak is bad enough it can trick the ecm a bit by giving a false temp reading thus changing the fuel mixture

it's not leaking any coolant.
could a dirty fuel filter be the culprit?
When an engine is cold, does the ECU send more or less fuel to the engine? Could my fuel pump not be up to the task of delivering normal op temp amounts of fuel to the injectors? I'll do some fuel treatments, injector cleaner and fuel filter and see what the change is like.

YOu said you have a lot of power when cold and no drivability problems. THerefore I don't think it's lack of fuel due to plugged fuel filter or bad fuel pump. If you did, you'd have studder problems and no power.

which is why I'm so confused.....

Whem cold more fuel. The fact that things change at operating temp leads me to believe it's sensor related. No codes, though, eh?

 

I think what I'm trying to figure out is why the engine runs great when i first start up, and it leans out once it reaches operating temp.

 

I'd bet money you have a bad MAF.

 

those vw were always bad for o2 sensors, my buddy always was getting your exact issue, no power at all but no codes on computer to tell you what is going on

I do remember a friends catalytic conveter broke up inside and the car ran like yours also


but I would say it is a o2 sensor acting up with temp, maf sensor maybe not so musch from what you are describing


may want to look at theses items I dont know?

 

Thanks guys. If this thing would just throw me a friggen code I woulda solved this issue months ago. Maybe it would actually be a little bit fun to drive if it had ANY power whatsoever.

I'll go to my parts guy and look up prices for O2 and MAF sensor. I'm pretty sure its not that cat, I had to replace that not more than a year ago.

 

No, 2.slows are never fun to drive, even when they are running right.

 

Better than my wifes slushbox 1.5 in her xA. [:'(]

As stated it sounds like the o2 sensor(s) are shot.

 

Nope, it's going to be the MAF. Trust me.

 

I concur. The little 2.0 SOHC's aren't as complicated as the 1.8T or 1.9 TDI's. If it were abad O2, computer would throw codes and the car would run in open loop (very rich).

Do you get a funny smell from the tailpipe when it's acting up? If so, throw a MAF at it.

BTW, tell your poor mother to ditch that farvagnugen and buy something quality. Even a Honda or Nissan would be prefereable.

 

my sis has a 2.0 with only 150,000km on it, and its a little bit fun to drive. Pulls pretty hard through three gears (for a 2.0 POS). My mom's has 285,000km on hers. and Mean, my buddy has a Honda 1.5, and that thing schools the VW....both however lose to the D ....The D has 3x the displacement....yours however has almost 4x the displacement, crazy

My mom loves her Volksvaughen because it has never given her any trouble. I change the oil, and thats all the maintenance it calls for. Never given her a headache.Other big selling points are the gas mileage, and it is easier to park at the GO Station.....lotta ****ty drivers show off their ****ty parking at the GO Station.

I don't think that its an O2 sensor, mainly because its running lean, and not stupidly rich.

I believe it could be the MAF sensor, I worked at a golf course all summer and it was always very dusty there. I had to clean the air filterevery week, I'm sure the MAF didn't like being cleaned all the time, maybe i ****ed something up when i cleaned it.