Hi all,

I somewhat recently acquired a 1996 W202 that had been sitting in a garage for many years. It needed quite a bit of work to get road worthy again (fuel pump, fuel filter, brake lines, brakes, tires, etc.) Car was running quite smoothly after the work, then after a few months, it began to hesitate intermittently while driving. The problem got worse and worse and I eventually brought the car to a local shop as I did not have a scan tool handy or work shop at the time. They told me it was throttle body, and cleaned it out with throttle body cleaner. The problem was slightly better, but still not fixed. I then ran Sea Foam through the intake a few times, and this too seemed to help the problem slightly. Assuming the throttle body itself might be defective, I purchased a throttle body on eBay and installed it, to no avail. I have also replaced the MAF, spark plugs, coils, and EGR valve and cam sensor. The strange thing is, I am able to prevent this hesitation if I do not leave my foot in the same position for too long. As long as I keep throttle moving up and down, even a little bit, it won't hesitate, even on a long drive.

The car is throwing a few codes:

P0341: Camshaft Position Sensor (replaced, but code returned.)
P1340: Camshaft Position Sensor "A" Bank 1 Sensor 2
P0400: EGR Flow Malfunction
P0325: Knock Sensor 1 Circuit Malfunction Bank 1 or Sensor 1 (Have new sensor, have not installed yet)

I should also mention that the oil light is on despite car being full of oil and wiper fluid light comes on upon startup despite reservoir being full. All these sensors going haywire leads me to believe there's is some sort of short in the Cam or Knock Sensor Circuit causing a larger electrical problem. Using a voltage tester I was able to measure resistance in Knock sensor circuit and noted one sensor had almost zero resistance suggesting a short circuit. I will examine that wire and replace sensor.

One final note, shortly after replacing the the throttle body, the car began to idle high and cruise control stopped working. I replaced the module that controls these two functions and this resolved issue. When replacing I noticed the cover was loose that protects this module and the ECU. Is it possible that ECU is damaged and causing these issues?

Thanks for taking the time, any suggestions would be greatly welcomed!

Cheers,
Alex

 

Hello again,
To anyone wondering, the problem was a bad Cam Adjuster Magnet. This was causing an issue with the variable valve timing which led to stumbling. All codes except EGR gone now.