I had a massive oil leak at two of my cam seals which drenched the timing belt, I'm at 79,000 miles. I was about due for the 80,000 mile service anyways so I went ahead and got a t-belt job, they replaced the cam seals and plugs as well as the cam tensioners and valve gaskets which fixed my oil leak. Also for the 80,000 mile service they replaced spark plugs, drive belt, and drive belt tensioner. They also fixed a vacuum leak. The coil packs were also replaced at 72,000 miles. Before I took it in the car had been idling rough and when my AC is on I get this griding/low humming sound when I'm driving between 20-40 MPH when I let off of the accelerator. It's not very loud but you can feel something that I describe as grinding in the steering wheel and gas pedal. I know it's not just me because my wife complains of the same thing. Anyways, I was told the grinding is probably the tension on the drive belt which should have been fixed with a new belt and tensioner. Now after all of this work it still idles just as rough and the AC still makes the same noise. I also know it's the AC because if I turn it off the noise completely stops.

I had the AC serviced a couple of weeks ago and it was about a half pound low so I had that refilled. They did a full check on the AC and told me it didn't have any leaks and looked to be fine. As far as the rough idle it stops when I put the car in neutral, usually seems worse in reverse. Does anyone know what could still be causing my problems? Any help would be appreciated...I hoped after $1500 my problems would be fixed.

 

1500 bucks is just to keep up the maintenance in our cars. When your AC is on it idles rough correct? Maybe your compressor is giving you problems, I know the compressor itself is really expensive and unless the car is stalling and throwing codes "I" and this is only my opinion would leave it alone, but if you want you can check with the dealer about it and find out.

 

No, the rough idle happens when in gear, normally sitting at stoplights. It will idle rough sometimes in park but it's the worst in reverse. If I put in neutral it goes away almost completely. It's more of a vibration when in gear rather then a rough idle. The A/C is just very loud, only when I'm like 15-45 MPH and coasting, if I turn off the A/C the noise stops immediately. If I'm sitting with the A/C on it runs normal, does not make any noises.

 

Well it does sound like a coil pack issue, what you can do is whith the engine idling and when is idling rough, you could go one by one taking out the coilpacks until you don't see a difference in the idle, that would be the bad one. Coilpacks are a normal thing that goes wrong with our cars.

 

All 6 coil packs were replaced about 10,000 miles ago so I don't think that's the cause but you never know. I took it back in and they have checked all of the mounts, vacuum lines, etc and didn't find any issues. They also said it's not missing or anything and the engine is running good. They are telling me it's definitely the compressor going out which is causing the noise and the idle issues. They've quoted me 950 to replace it but about 650 of that is just for the compressor itself. I found some remanufactured ones online from 350-400. Does anyone know how hard of a job replacing the compressor is? Also, anyone have any suggestions on where to pick up a compressor?

 

It could be your compressor, but I still wouldn't rule out the coilpacks, they go bad very very often.