You are going lean under acceleration, this is what causes the power loss.

There are many ways this can happen, from a bad vac leak (idle control valve hoses in particular, or a loose booster vac line) to a bad fuel distributor or air flow "pot" that senses throttle opening.

The airflow venturi is what you see in the intake when you take the air filter housing cover off. Gently press the disk in the center down (engine off) and make sure it move smoothly. It's likely filty, carefully wipe all the dirt off the hole it fits in (the venturi) with a cloth wet with solvent. If it sticks or moves roughly, you have a fuel distributor problem, most likely a scored plunger.

If the flap moves properly and you still have trouble after cleaning it, you need to check the air/fuel mixture with a VOM meter that reads duty cycle. A milliamp meter is also useful, although not required.

Hook the meter up with the black lead in hole #2 on the diagnostics connetor (the round one with a screw on cover on the fender) and the red lead in #3. This should read either 50 or 70% with the key on and engine not running, then 50% until the engine warms up. As the engine (and oxygen sensor) heat up, the reading should start to change. It must be 50% or a bit higher (sometimes you need to set it around 40% to get to get good throttle repsonse) and it MUST constantly change up and down. If it swings way high and stays there, you have a vac leak that is allowing too much air in for the feedback system to compensate for.

The adjustment is by inserting a 3mm allen wrench down the little "tower" on the intake manifold (there is a hole in the air filter housing to allow access with the filter in place) and pushing down to engage the actual screw. You can miss the 3mm allen hole, so be careful, please!. The screw fitting can then be turned SLOWLY to change the mixture. Takes about 20 sec to stabilize after adjustments, so go slow.

If the mixture cannot be adjusted, you have other problems.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!