Hey Guys,

2 months of owning the Jag and I love it. I love it more than I thought I would. I just installed a Pioneer double din with backup / xm..etc.. and I love it even more.

Although, ever since I bought the car, it has had a rough idle ONLY with the AC on. The car runs very smooth at all speeds with the AC on or OFF, but it has a rough idle when stopped at the light with the AC on.

I used BG44k (2 times.. not back to back) and it hasnt changed this. Where should I look? MAF?

The car is almost out of warranty and when I did the Pre Purchase inspection, they said the fuel injectors were gummed up and I needed to do their service ($200+). It's odd that the car runs perfect with the AC off..

Anyone ever had this before? It's a 2008 S-type 3.0.

Thanks,

Joe

 

Doesn't sound like injectors or MAF. More likely an a/c component (the compressor), since it occurs only with a/c on. Frankly it sounds like either they don't know what they're doing or are hoping you won't find the true cause till the warranty's gone.

I'd put the details in writing (what you know & what they told you, with dates) and go ask them to fix the problem, leaving them a copy of the written details. That way you have good evidence this was present during warranty coverage and you've asked for it to be fixed.

(Over here that's the kind of evidence you could sue on if it turned out to be necessary - but it usually isn't.)

 

What do you mean by rough idle. RPM change or sound that is different when A/C is engaged?

 

The sound should change slightly, because rpm will be higher, whenever a/c is on (and compressor activated). As the compressor cycles on & off, rpm should rise & drop a little to compensate for the extra load imposed on the engine by the compressor.

The above would not be a "rough" idle.

A rough idle would be where rpm is varying for no apparent reason, often felt and/or heard as varying engine revs, possibly with actual shaking of the car.

Several things can cause a rough idle, commonly an air leak, but also a failing pulley among other possibilities.

 

Hi Guys.. Thanks for you help.

The RPM does not change and its almost like a loopy idle, with no change of RPM (Based on the Tach). It does shake the car. I have a good service advisor as he has helped me out in the past, freebies...discounts.. but he did mention the fuel injectors were clogged when I did my PPI. I just wanted to see what everyones opinion was on the rough idle with a AC on problem. I may try to disconnect the battery and see how it acts.. I just hate going to the dealer. (Miami, Traffic, Hertz Loaners..pain in the a$$!)

Thanks again,

Joe