I have a 1992 Q45 with TCS.I removed my intake plenum to repair some fuel hoses and injectors(removed injector rails). After putting back together and starting up the Q, i get a high idle (around 2000rpm) along with a "transmission malfunction" on the in-dash display. The idle will not go down below about 1100 until i put it in gear and then is drops to about 800rpm. i never had the high idle or the "transmission malfunction" before.

WHen I drive, the transmission does not like to up-shift when reaching cruising speed. I must let off the accelerator pedal completely and then the transmission will up-shift (3-4 gear) otherwise, I cruise around in 3rd at higher rpms. There does not appear to be any problem in the downshifting.

I am thinking that I have a vacuum leak somewhere and that I must have torn/cracked a hose or missed something when I put it back together (i took it all apart and reassembled but did not find any problems - I have previously removed and re-installed the plenum on 2 other occasions w/o any problems.)

Does anyone know what/which hose(s) the transmission uses to receive a vacuum?

Anyone have any ideas on what could be causing my problem?

I am all ears.

Thanks

Jeff

The only thing I would suggest, due to the weird behavior of the trans is to check that the TPS did not get screwed up somehow (misaligned perhaps, stuck at WOT or idle)??? I'm guessing the TCU relies on knowing the throttle input in order to better determine when to downshift, rev to redline, etc... As far as the vacuum leak perhaps when mucking with the fuel injectors the FPR hose was damaged or loosened? Sorry I can only guess. Put your head under the hood and listen for a rush of air to find the leak.