We have a 2005 STR6 which we recently drove over 5,000 miles on a cross country fifteen western state vacation. The car is "like new" with only 21,000 miles. It worked perfectly until just at the end of the trip as we approached home. Then I noticed that the boost started cutting out. In other words, when I pressed the gas there was no supercharger boost, only the power of the engine, no throaty supercharger sound. The automatic transmission would downshift as with any car and the RPM on the tach would jump up noticibly, but there was no added supercharger power (or sound). It was very noticible. Then after a while of driving the supercharger would kick in again when I pressed the gas. I started timing this and it happened regularly about every 1 1/2 to 2 minutes. That is to say, the supercharger would work for about 2 minutes, then nothing... and it would go with the engine only power for about another 2 minutes... then the supercharger would work again.

Upon return I took it to the local Chrysler dealer in Springfield, Missouri and explained the problem. I told them about the 1 1/2 - 2 min. intervals and told them that when the car is first started it works perfectly and they would have to drive it for some distance to observe the problem. They kept it a week and then called and said it worked perfectly and they couldn't duplicate the problem. However, I drove it home and the problemm was still. Obviously, they didn't drive it for any period of time or they would have noticed the problem of the supercharger cutting in and out -- because it is very noticible because the car not only sounds different, but there is no power. It's like a day and night difference in performance.

Now I don't know who to turn to or what to do. The problem is still there, the supercharger only cuts in part time... about every 2 minutes. This could be potentially dangerous, for example, if I were to pull out to pass someone and press the gas expecting to be rocketed ahead... and nothing happens (except for regular engine power). When this happens at 60 mph. it feels like I'm driving our Ford Windstar van... the transmission downshifts and the RPMs go up, but there is no kick in the pants acceleration.

Because it happens regularly at apx. 2 min. intervals both ways -- i.e., it works or it doesn't work -- it seems to me like that would indicate some sort of electronic malfunction rather than a mechanical problem. It would seem like a purely mechanical problem would be irregularly intermittant or full time not working. But I don't know anything about superchargers or how this car works. Obviously, the local Chrysler dealer mechanic doesn't either. Of course, they don't get a lot of the rare STR6s to work on. (In fact, in Spokane, Washington when we took it in for the regular synthetic oil change the mechanic came out as we were ready to leave and thanked us for letting him work on our car. He had always wanted to see and work on the supercharged Crossfire.)

I would really be grateful for some ideas, suggestions, solutions to be able to take back to the dealer and tell them what the problem is, or what to check, or where to look or what to do. I was tempted to tell him, "Would you mind just calling the Mercedes service manager and asking them what to do?"

I should say also that it doesn't matter if I'm driving slow in city or fast on the highway... or if I'm driving at a steady speed or accelerating... every apx. 2 min. it just stops working. No boost. Keep going for another apx 2 min. and press the gas and suddenly it works again.

Thanks for your help.