Slow Acceleration on 420 SEL
 

The car accelerates slow. It seems normal for regular city driving but if I need to accelerate quickly (pulling out into traffic) it is slow. It is as though there is no difference between when the pedal is half way down or all the way down. Also, if I am on the highway and go to pass it does not kick down. It will accelerate to high speeds but do it slowly. What could this be? O2 sensor? Or what about linkage--I do not put very many miles on the car and the linkage could get sticky I suppose? Any ideas? Thank You

have you checked the fuel filters?

I have the same problem but maybe cause I have the slow 3.8L?

if you press accelerator to floor should kick down into first if your kick down switch is ok. My Euro500 Se with Euro 420 engine is no Corvette eater off the line but given enough road,Oh well to late at night for braging........
William Rogers...........

I used to get frustrated about the acceleration issue on my '91 420. I thought it was just a smaller engine issue because I've driven the 5.6 liter and it gave more of a kick off the line.

After I had the transmission serviced (fluid/filter change), I discovered that kick down had not really be working. It works now and while I don't get pinned to my seat, acceleration's better than it was.