My '92 300e has been performing poorly lately and I'm not quite sure what the problem may be.

Symptoms:
- Acceleration is sluggish. Occasional hesitation regardless of how far the accelerator pedal is pushed.
- Gas mileage is very poor ~11mpg
- Once the throttle is open, it seems to run more smooth

I've installed a new fuel filter, wires, plugs, distributor cap, and rotor. It almost seems like it may be running too rich or maybe a fuel delivery issue.?.?

Any suggestions are greatly appreciated. I'd like to have a better idea of what the problem might be before I go ahead and replace parts. Especially given their cost.

I had a similar problem on my '93 300ce.

I disconnected the o2 sensor under the carpet in the passenger footwell (m104 engine,, not sure if your car has same?) and the car accelerated fine ,,, so I replaced the O2 sensor,, problem solved.

Worth a try before you replace anything else,,, I think the new sensor was about $120.

Take the money you are about to spend guessing about the cause, and have a MB independent shop diagnose the actual problem. That will be the most economical approach. Do it yourself is great, but guessing is expensive.

Just my opinion.

Steve

I agree with steve... I found a local German Autoworks shop and got the point across that I was aware of the problems I was having and that I intended to do the work... after i gave him 80 bucks for looking at it he was happy and told me what he would do. I had the same problems... I have a 95 E320 with the 104 motor.

I ended up replacing the Engine Wiring harness that was very VERY neccessary, then replacing the plug with the right ones... The resistorless ones that everyone talks about on here (I'm sure that someone will chime in with it). I also replaced the sparkplug connectors (3 of them) and that was it. No more sluggishness and no more hesitation when downshifting onto passing gear. If you search my name you'll find the posts where I asked these same questions.

Good luck dude,

justin