I really dont think this is fuel related because the rpm's drop off so suddenly and return like almost someone is turning on and off the ignition.

Once i am up to speed it seems to smooth out, could this be my coil? or distributor cap?

I had replaced the plugs,cap,rotor,and wires about 20,000 miles ago.

 

its a 1992 240 ? (guessing that your nickname matches your vehicle). that has OBD that you can read without any tools, I'd check to see if any fault codes are stored. See...

Engine and OBD Diagnostic Codes

note there's codes with the jumper in position 2 for fuel injection, and position 6 for ignition

 

That seems pretty complicated.

 

you open your hood, find the little box just forward of the left strut tower, open the cover on the box, put the jumper thats next to it in hole #2, turn the ignition key on (but don't start the car) and push the button on the box for 2 seconds (one-one-thousand,two-one-thousand), and the LED there goes blink... blink.... blink. thats code 1-1-1 (no errors). if it goes blink-blink....blink-blink-blink....blink, thats 2-3-1. push the button for another 2 seconds, until it gives you the same code. 1-1-1 means 'no code'. now, key off, move jumper to #6, key back on, button for 2 seconds, and read ignition codes until you get 1-1-1 or they repeat. the codes are quite slow, like 1-1-1 is 1 second on, 3 seconds off, 1 second on, 3 seconds off., 1 second on, off... after you read all the codes, if either #2 or #6 wasn't 1-1-1, then push the button for over 5 seconds and release it, the light should come on, then push it again fro over 5 seconds and release, and the light should go off. now if you push it for 2 seconds, you should get 1-1-1 as you reset the codes.

seems simple enough to me. best part is, no weird code reader is required

 

92_240...it's pretty straightforward. The corresponding diagnostics to the x-x-x are pretty easy to find. Just read Pierce's great explanation of what to do. It's pretty basic. Don't let it intimidate ya. Good luck

 

I've got the same problem, only mine gets worse as the engine gets hotter, i can barely accelerate when it's a hot day out.
I have replaced my fuel injector, distributor cap and rotor, a few likely cases but it still seems to be giving me problems when i try and accelerate quickly

 

turtle; what year 740? if its LH2.4 (1989+), are there any OBD codes?

what do you mean, you replace your fuel injector (singular) ? there are 4 injectors, they almost never go bad, far more likely is problems with the fuel pumps, relays, wiring, etc.

 

You're right, i think it was the fuel filter, an metal cylinder on the driver's side underneath the carriage.
It's an '88 740.

 

well it does not matter now. When i was tinkering i tilted the battery up and the terminal arced on the brake line.....causing a hole. at that point i gave up and scrapped her.



now i am the PROUD owner of a 92 940