Last week i checked the air filter in my '91 740 turbo. After that the engine idled rough and there was almost no power frome the turbo. When the turbo kicked in the car would hesitate and my rpm's would raise as the engine tryed to cover for the turbo. I drove it up and down the street and blew out anything that would be clogging it. That worked and the car drove fine. This morning, however, while I was driving it started hesitating really bad and I couldn't accelerate at all. Then the car stalled just as I pulled into a gas station. It would start and run but only for a few seconds. I checked the air filter and there was a pile of foam sitting on the air filter, right in front of the intake hose. It had fallen from the top of the air box. So I'm assuming that's what's wrong with my car. I managed to get it to run and I hobbled home. It'll drive but it still hesitates under moderate accelleration. The turbo will push the car but then it seems to try to stall as the engine takes over for the turbo. Is it harmful to the turbo/engine to drive it with the foam in there? Will it just blow out or can i take it out? If anyone knows i'd greatly appreciate any help they could offer.