According to the owners manual every so oten you should take your car out, and run it at or above 3000 rpm to improve performance. I have noticed that when I take mine out on the highway after all of those city miles it kinda' feels like your discription, the problem I have found is that if you are running at 3000 rpm you are doing 80mph, and in Indiana that can get you a big ticket, but it does seem to take out the cob webs, and after a few miles the symptom is gone. 1984 633csi atomatic. At 55mph it feels like I have air bubbles in my fuel line. Cruses fine at lower speeds. When I hit the gas it reluctantly takes off. And, of course, its tempermental! It just started with my last fill up of Texaco 92. If the octain in the gas was not quite up to par, would my performance chip cause the above symptoms? (Its an overpriced Dinan chip) What is a good way to check my fuel presure while driving 60? and what should it be at? I have a fuel pressure gauge.