95Jetti III Getting engine codes
 

Hi everyone I am a new member. I bought a 95 Jetta III 2.0 engine It seams to break up or surge whan I am driving it. Also seems to be using a lot of gas. The check eng light is on and can't seem to get the code to read by jumping pin 4 & 15 on odb port. I thing it might be the mass air sensor I took the hoses off and there was oil on the air filter and in the maf and hoses I cleaned it all up and put in new air filter & tried cleaning the maf. The car starts and idles pretty good but when I drive it it seams to miss or break up & seems to be using a lot of gas. If anyone could tell me how to get the code or help in any way it would be a big help... Thanks:)

Check the voltage of the mass airflow sensor, should be quite low at idle. and slowy open the throtle body and watch for any big jump. also, check the voltage on the o2 sensors.

is there a rotten egg smell in the exhaust?

check engine light still on
 

The voltage on mass air seems fine. & no sulfure smell in exhaaust. stil have check engine light and can not pull the code. I found under the back seat the tool that came with the car to make the code blink. But it will not make the codes blink. The car idles fine and starts up but when you take off and are driving it hesitates or seams to surge maybe a misfire or a fuel injector. I changed the fuel filter checked the distributer cap for cracks, check most of the vacuum lines but I still have the problem. I do need to replace the cam case vent on the valve cover as it is cracked but I don't think that would cause the engine to do this...... HELP Thanks

Having same accelleration stumbling, no light
 

I've had the same issue w/ my 95 2.0 for years.
I've owned the car for 12 years, and it started doing this about 3-4 yrs ago.
I don't know if yours is the same, but my problem will disappear (at least temporarily) by restarting the engine. Quickly, with the engine at temperature, the problem returns. Sometimes, I can coax the car back to normal by driving up one gear (for example use 4th gear when 3rd normally applies) until the stumbling stopped.

I've tried almost everything: clean and swap maf, replaced 02 sensor, new vaccuum lines on air box and EGR system, replaced rubber intake assembly with aluminum rigid, ignition, wires, cap, distributor, fuel filter, crankcase breather tube, ECM swap, catalytic, and stuff I'm probably forgetting at this point.

Today I'm going through the two vacuum valves situated near the air box (one for EGR, the other is for the airbox flap) and replacing the hoses (although they still appear to be pliable and connected).

I haven't replaced the idle air control valve (mine is the early type that is seprate from the throttle body on the driver's side of the intake).
I have not replaced the cam case breather, but I have removed it and inspected it.
The car has been on the VW diagnostic reader several times and the code history is not much help.
At 160k miles, this car has been otherwise well kept and serviced (rebuilt top half, timing belt, suspension, clutch).
Many of the fixes I have tried improve the stuttering or stumble on acceleration, but stubbornly the problem returns.

When it's running good, the car is really fun to drive. Restarting it all the time is annoying and bad for the starter (mine is replaced of course), and some days I want to drive it into a ditch becasue of this particular problem.

Wish I had a good answer for you. If one of us can fix this problem, it would be cause for celebration.