bad mechanic?? now stumbling

[diablos991]

So about 8 or 9 months back me and a friend changed my timing belt, front seals, idler pullie, etc.... however we did not change the water pump. well I learned my lesson after having to pay a shop to install the water pump yesterday , because I don't have the means to take on that job again. but now that I have my car back it is idling really crappy like. stumbling and jumping around between 300-800rpm.

Could this possibly be the timing belt installed incorrectly? what are some steps that I could take to properly diagnose this issue before taking it back to the mechanic that installed it?

'95 Eagle Talon TSi

bolt -on mods list:
K&N FIPK kit, Greddy Intercooler Piping, Greddy Type-S Blow Off Valve, 2.5" Downpipe, 3" Catback Exhaust, Greddy Profec B-Spec II Electronic Boost Controller

 

[blackGSX2g]

Does it run bad through the entire RPM band? If so, take the timing belt covers off and make sure that all of your timing marks are lined up. Its possible they left it a tooth or so off.

 

[diablos991]

It only happens while idling. the rest of the rpm band seems fine. It's almost like its missing/sputtering.

 

[Old Mitsu Tech]

Spray some Gumout or equivalent carb cleaner into the intake tract to see if it tries to straighten up. If it does, and your problem is only at idle, likely it's a vacuum leak.

Spray around your intake runners where they bolt to the head also.

You never know.

 

[diablos991]

Thanks. it ended up being a vacuum leak. but now its back to the mechanic because the water pump that just got installed is leaking antifreeze.

Thanks again for the advice.