I am having an intermittent bucking/hestitation again on my 92 SC400. This happened a couple of months ago, and went away. This usually happens when accelerating under 2000 rpm, when the transmission changes gears but not consistently, and sometines at around 80 mph. Could this be caused by a bad cam shaft sensor?.

 

Have you done plugs and wires, fuel filter, air filter, checked for vacummn leaks. Prob. wouldnt hurt to do a MAF cleaning. I usually find a bottle of fuel injector cleaner will help.

 

Thanks, have not done any of those mentioned, except for Lucas or Techron, in the gas tank occasionally. Problem is so intermittent, it will run good for months, and then revert to the hesitation. Could the 10% Ethernol in the gas be an issue.

 

If it was I think it would do it all of the time. I always recommend brand name, highest octane gas.

 

All gasoline has been with 10% ethenol for a few years and is approved for all gasoline vehicles. i highly doubt that gas is the issue.

 

Thanks, has anyone had this issue though. The fuel filter was actually changed 6 months ago.

 

Does it feel like the car shift to OD prematurely and leave you with no acceleration?

 

Its like a flat spot, when accelerating between 15 and 2000 rpm, and the rev needle goes haywire, and the check engine light flashes. It somtimes happens at around 80 mph. I am leaning towards the cam shaft sensors (2). Car has 225,000 by the way, as it tends to happen when tranny shifts.