Two Second Acceleration Lag – Fuel or Air Flow Problem? (260E)

[EricSilver]

Car: 1989 260E, 198,000 miles.

There is a one to two second lag in acceleration when I floor the accelerator (but without engaging the kick-down switch) whether from standstill or at speed.

The pedal will contact the floor, and the fuel economy needle will move, but the tachometer will not budge for a second or two. Then it surges, making for a jerky ride. I was initially told this was a fuel delivery problem, but I am wondering if it could be an air flow issue.

I know I am running lean. The last thing I did to the car was replace the Thrust Cutoff/Throttle/Decel micro switch to correct a fast idle.

Help. I want smooth, steady acceleration.