Lex 400

Thanks for all the suggestions. It is a 92 LS400 and i keep it properly maintained just had a tuneup and oil change 3 week ago. I will try a new wire set first it is pretty much the only thing i have not changed in a long time.

My LS 400 starts jerking at about 40mph. It seems that the faster i go the harsher the jerking gets. the rmp needle goes down a couple hundred rpm and then back up to normal when it jerks. It also only jerks when my foot is on the gas pedel and moving down the road. If i let go of the gas pedal the jerking stops. The jerking seems to be a random because it does it whenever it feels like it. There are times when it is just fine. When i pull up to a stop light it seems to idle fine around 600 to 650. I would apreciate any ideas on tracking down the jerking.