Well when i first bought my '92 liberty FWD ej22, about 2 months ago i got rid of the that stupid intake silencer thingy and the original pannel filter.
Sounds great. not sure if i got any performance from it but it certainly sounds like it goes harder

Everything was running perfect as far as i can tell....
About two weeks ago i modifyed the exhaust, I was going to to clear out the center cat but it was already straight through.
replaced the rear muffler section with a straight through 2.5" section.

Sounds F*&$ING SPECTACULAR, and it definitly helped with top end power.

Before last weekend i had only driven the vehicle twice maybe three times since installing the exhaust. everything ran beutifully.
Last weekend I took the liberty for a run to hobart (about 4 hours drive each way). Did not drive the car particularly hard. As i was aproaching a round about on the drive back I realised that it was idling at about 1500rpm. I have never noticed this before, but just assumed it had somthing to do with the long drive.
but alas that was not the case, when i start the car it revs at about 1500. if driving down the road at say 15mph and the clutch is released it idles at about 2000. when the clutch is released as the vehical is coming to a stop the revs rise to about 1500 the gradualy die down to where it should be (750rpm) this takes about 5 to 10 seconds..........
Any ideas...... i'm stumped.. oh BTW it isnt throwing any error codes
Just one more thing, does it seem odd to anyone else that i have ALOT more LOW end power when the car is cold..... any other car i have had has lacked low end power when cold and reved out better than usual.. (more compression i suppose)