I just had my 07 hatchback in for a bunch of work and had the timing belt, water pump and idler replaced along with a further host of issues - front struts & mounts, outer tie rods, stabilizer bar links & bushings, both CV axels & replacing the failing AC compressor.
previous to the service the car would idle rough - but ONLY with the AC on, accompany'ed by a grinding sound. With the AC off it would idle normally. I had the compressor verified bad by two different mechanics.
post service - the car now idles very rough, surging between 700 and 900 rpm at idle. it did NOT do this before the timing belt service. there is also a small vibration through the steering wheel at highway speeds (on fresh brand new blacktop no less).
the original AC compressor i supplied to the shop who did the work was diagnosed as defective, causing the car to run under strain. the unit was replaced with one provided by the shop through their parts supplier.
the shop told me that its possible that its a fuel management issue that will resolve itself after a day or so of driving. I suspect that the timing belt is off by a tooth & that the AC compressor i provided was actually good.
is there any way to diagnose this as being out of time so that i can address the issue properly with the shop that did the work?
if the timing IS off by just a little bit, is my engine at risk? or just going to run like crap?
any help is appreciated