revs jumping when changing gear and low mpg

[wattywatts]

hi found this place while desperatly searching for an answer to my problem and hope theres someone here who can help.

the car is a 2001 y reg alhambra 1.8 turbo petrol.

basicly as the title says the revs jump up when you go to change gear, when sat stil you can sit and rev the engine fine and it sounds perfect, but when your driving along and go to change gear, say for instance at 3000 rpm the revs will jump to neally 3500, i know its deffinatly not my driving

if you drive slowly and take your time between gears you can almost ignore it, but if you want to pull off quickly, say from a junction it sounds terrible as if youve missed a gear.

it gets worse the higher the revs.

another factor is that it only does about 10-15 mpg at best.

ive taken it to several garages and come away no wiser, there is a specialist locally that deals with all the computer side of things, but for some reason none of the obd things will connect to the cars computer so noone can read any data.

there are no management lights etc on and they do work as i disconected the maf and started her up to check and the epc light came on, then went off when i reconected it.

im at a loss now as i dont want to spend hundreds in a seat garage for them to not even find a fault.

any ideas greatly appreciated.
cheers

[KeithOT]

Did you sell it? I've just bought this same model from a garage in Baglan & it does just this, not sure about fuel consumption as I only collected it yesterday.
Today (6/12/10) I ran a scan for DTC codes & got a 16518/P0134 O2 sensor circuit no activity detected (bank 1 sensor1) This is probable cause of poor fuel consumption & probably the rev up problem.

[KeithOT]

A suggestion from another forum is similar to the diesel with a similar problem it may be the clutch switch which may or may not show a fault code when scanned. It is cheap to replace but not that easy to get at have to remove bottom of dash.