1997 850 T5 runs perfect as long as you don't drive it!
 

Hi Everyone, I am at a loss here. My Sis has a '97 850 T5s that runs accelerates, does great as long as you have it in park. Will red line on rpm no running problems at all in park. You try to drive it and it coughs, sputters, shudders, shakes and makes you think it is coming apart at the seams. I replaced air filter, plugs, wires, cap and some duct taped hoses that my older brother "fixed" for her and still no change. No cel or any other lights on. Any ideas??

some possible areas to check out: Fuel pressure/fuel pump/pump relay - test the pressure at the rail, consider swapping out the relay. clogged catalytic converter (see if pulling out an 02 sensor changes anything). Have the coil tested. inspect the MAF and intake & idle valve for cleanliness.

Thank you mt
 

Thank you mt but I stumbled across the problem by taking one system at a time and going forward. Not sure if all 850's have this but on this car just in front of the turbo on the engine plate to the intake side there is a vacuum port. No idea what it is for but it had a split vacuum cap on it and a $3.99 cap kit from Autozone fixed it. It is directly down from the master cylinder reservoir on a flat spot of the turbo mounting plate in case anyone else has this same problem. Must be beyond any of the sensors because the car never threw a single code. Drove around with the gas cap loose to throw a cel so I could have the dealership scan it for me and it was clean except for the code I caused. Go figure. Just wanted to let everyone know what it was and where to look in case someone else is having the same issue. Thanks everyone that read it and thank you very much for the input mt! Have a great day and week everyone.

good deal. I forgot to mention to do a visual on the vacuum lines. I had a similar deal where my daughter's 850 started throwing codes - turned out one of the vacuum line caps on the vacuum tree was missing. Had to get the same $3.99 kit from Autozone - with all the various size caps that you'll never use except for the one that fits...