Fuel/throttle issues

[Momentum]

Hello all

I am hoping for a bit of help with an issue with my 1993 E320 Coupe. The issue is that if I am cruising along and take my foot off the throttle the revs drop instantly by say 500 revs and the car feels a if it is losing speed quite quickly. If I press the accelerator it returns to normal.

Although I could live with this there is another occasional occurrence. I do quite often use the gearbox manual option (it is a 4 speed) and three times now I have put it in second to accelerate quite hard and when I change up I have no control over revs. Pressing the throttle does nothing and the car feels like it is cruising to a halt, not suddenly but at this point I will be looking to pull up at the side off the road anyway. I then put it in park and the car will start again and run fairly normally.

I will take the car to a garage soon but any pointers might help speed up the process as I do fear this dragging on. Many thanks

 

[John Jones Jr]

Possibly the engine wiring harness has started to degrade? It's certainly not an unknown issue so it might be worth opening it up and inspecting it.

 

[RichardF]

If it is the engine harness, the worst degradation will be where it gets hot. Look around the injectors and coils. On affected cars TB harness will probably be poor as well, so also worth a look.

Unless you have evidence of these being replaced it's not worth doing other stuff until they've been checked/resolved.

Si-leck motorsport will rewire the harnesses, I've just received them back and waiting for a break in the weather to fit.

My lower engine is also affected but less complicated, so can do this one myself.

 

[RichardF]

To add to the above read and clear the codes, see what re-appears and this'll be a starting point.