I was having problems with my 91 940t. I couldn't get the car to rev over 5000 rpms. This only happened if I was on the interstate doing 55 or so. I could floor it from a red light and I would go through 1st into second with out bogging down, however if I would keep it to the floor when it would hit the 5000 mark in 2nd it would act as if it was starving for fuel, and buck. The car was also sluggish. I've had the fuel filter changed, fuel pressure test(48-52 lbs) air filter changed, new plugs and wires, had a back pressure test done and it showed I did have back pressure. The gauge went up to the number 2 when the guy reved it to around the 5000 mark.(not sure what the increments of measurement were) Had the CAT changed at midas. Now the car is much more peppier not like it was before all of this, but better. So I drive it on the interstate and it the motor winds out pretty nicely seems to be not as strong as before but much better still. I go to accelerate agian and I hit about 4500 rpms WOT and the car gets weak and dies on the interstate. I try to start it and it barely runs. Finally get the car to run but now I cant get past 4000 rpm WOT it just dies as if its hitting some sorda rev limiter all power stop until I let off the gas. Please somebody give me some sorta direction to go. The car does have turbo+ and it has 151,000 on it!! THanks in advance!!