throttle problem 87 420SEL
 

Any 420 owners out there ever experience a throttle, that when you let off of it (usually most noticable on the highway) you can feel it wavering up and down? It gets so pronounced at times when I'm backing up after a shot run to the store, the car lurches back and forth....driving me crazy....I changed out the computer mod with a spare. Didn't make any difference......Thanks in advance for some ideas.....

Dave Bunker

It sounds like you might be going in and out of decel cut-off. I don't recall what all is in the circuit on a 420 but I would verify at least the operation of the throttle idle contact.

To verify the problem you could disconnect the EHA once the car is warm (won't start well cold with it disconnected) and drive it. If the problem is gone then the decel function is a likely candidate.

Yes! And Thanks
 

I was going to post about this on my 87 420 but figured maybe it was just me. I don't really feel it on the highway but when letting off the gas around 40-50mph, I can actually see the tach needle cycle up and down a few millimeters slowly as I coast. I'll have my mechanic look at the throttle idle contact.

John