1989 740GL with 315K on the clock. Here is the problem : My wife was driving down the road today at about 40mph with the air on in 85* weather. All of a sudden there is no power and the engine seems to go to idle. She pulls off of the road and puts it in neutral and steps on the gas and engine revs up. Then puts it in drive and no problem. This is the 3rd time in the last 2-3 months that this happened. Note there are no codes and all come up clean. It's like the TPS doesn't know where the throttle is . Both fuel pumps and filter are new (6months) . Both FI relays have been replaced. New crank sensor and new O2 sensor in the last 6 months. The car does not stall it just will not rev when this happens. Any thoughts here?

 

She have cruise on? So, once she looses power, stepping on the gas does nothing, but it idles like she let off the gas. I would think the throttle body just closed and the engine went to idle. Why, I don't know.

 

No cruise in the car. Stepping on the gas does nothing as if the TPS is lost. All she did was pull over and put it in neutral and the engine would then rev when you hit the gas. She would let it go down to idle and put it in drive and it would go as if nothing is wrong. I checked the codes and none are set. As I mentioned this has only happened now 3 times in the last 3-5 months.

 

My car is having a similar problem, when I give it lots of gas (WOT) between 2-3k rpm, sometimes the car will have no power, no pickup.

I've done some of the solutions that you have tried, replaced FPR, new fuel filter. That seemed to help... a little. I was going to check the in tank pump, but since you've said yours is new, i'm not so sure that is the problem.

Is your car a turbo? I really think it's a fuel delivery issue, at least in my case, but you've presented a real puzzler! I'll keep thinking and checking and see what you come up with.