Debugging stumble on acceleration when warm Options

[solex]

On my past few drives the car has been stumbling when I accelerate specifically when warm and in every gear except first, in my 2.0L D-Jet in a 75'

A few of things to note:
- Ground strap at transmission has been cleaned
- Installed a second ground at battery ground point to the engine fan
- New spark plugs Bosch W175T2
- Engine compression 134-145 all cylinders
- Fuel pressure set to 28 psi
- spark plug new wires
- 123 Ignition curve 2 with vacuum advance attached, 10 degrees advance at idle
- Injectors have been rebuilt by Mr. Injector
- All vacuum hoses have been replaced
- AAR is in working order and has been oiled

Not really sure where else to look, the engine idles < 1000 but is not smooth at times jumping +/- ~ 200 RPM

Any advice would be appreciated.

[rjames]

Have you tried adjusting the fuel mixture with the knob on the ECU? Clock-wise a click or two might fix your hunting idle.

Stumble sounds like either your TPS as wndsrfr pointed out, or car is running too lean, which could also explain the hunting idle.

[BeatNavy]

Have you tried adjusting the fuel mixture with the knob on the ECU? Clock-wise a click or two might fix your hunting idle.

Stumble sounds like either your TPS as wndsrfr pointed out, or car is running too lean, which could also explain the hunting idle.

(IMG:style_emoticons/default/agree.gif)
I think this is where you need to look. Where is the stumble? Immediately coming out of idle? Or at all RPM's on acceleration?

Hunting idle is usually a sign of being too lean. Stumbling on acceleration can also be explained by going suddenly too lean (or, more precisely, more air as throttle opens not compensated fast enough by more fuel). If it happens right from idle, enriching your idle mixture could help. Stumbling can also be caused going the other direction (too rich) or in general too big a change in fuel mixture relative to the amount of air the engine is taking in. In your case, I'm betting on lean.

The "dirty / worn TPS" situation is often a bucking at steady cruise caused by poor contacts with the traces. If you look at your TPS, you'll see there are also two other contacts that tell the ECU if the change in throttle is acceleration or deceleration. Make sure those are clean as well.

You don't have an Air/Fuel gauge do you?