I am having a slight hesitation under heavy to WOT acceleration. This happens in the upper RPM range, above 3900 RPM. The car will stumble for a maybe a 1/4 to 1/2 second and then power comes back on.
Today, I left the trans in 3rd and accelerated onto the highway. At about 110, the engine stumbled up to about 120, then I shifted into 4th and from 120 to 130 all was fine.
I also tried a high RPM run in 2nd, took the car to 80 mph in 2nd, and felt the stumble as well, but not as bad as when in the 100+ range.
Plugs are new, cap/rotor only have 20k miles on them. Fuel filter is new with only 10k miles. Car has 82k miles on it. Had the engine wiring harness replaced less than 6 months ago.
I think it may be the fuel pump going out on me. Can anyone tell me what the fuel pressure is on a '92 400e at idle and under load? I try and connect a gauge to monitor the pressure while under load.