loss of powere and response

[seaneh]

hi,
me and a friend recently bought a 205 gt 1.4 tu3 series to use as a rally car for our local motor sport club and today we repaired the exhaust as it was blowing on the downpipe. but after a few hours of it been repaired we noticed we were begging loose power and the throttle response was slow. and then it began to kangaroo and acted as if was going to stall when crusing at about 40mph at 3k revs also when we were trying to pull away from junctions it was kangarooing very bad. the thing is the elctrics are ok as non of the lights dimmed etc. can anyone help us here on this one?