525 M20 rpm falls when reaches 4000 rpm.

[emw525E34]

Happened twice today on this car!. Everything normal then pulls to 2nd gear nicely, once the rpm reaches 4000 rpm. Engine alost dies down!. Feels like sudden fuel starvation. When I slowed, its normal as long as rpm is below 4K, what could be the problem ?. Fuel pump going south soon ?. Fuel filter clogging ?. Or just a case of bad fuel ?. Or air filter badly clogged ?.

Never had this on this old car. Only one case of bad fuel a couple of years ago when it coughs for a few seconds under light throttle, then disappears. This time the symptom is reproduceable. ON idle, i can rev up to 3k or 4K like normal. But when its running I seem to hit this snag. Pls advise.

[632 Regal]

I think your on track here, check the plugs, wires, ignition system too.

Fuel pump going south soon ?. Fuel filter clogging ?. Or just a case of bad fuel ?. Or air filter badly clogged ?.