Have a 08 H3 3.7with PCMforless tune and magnaflow cat back. Ihave two problems 1) rough idle and 2) A vacum or sucking sound when hit the gas in park. Have about 150 mile since pcm install.

 

Just wondering if your problem has fixed its self? I would have thought someone would have responded to your issue by now. what's up with that? I too had a tune did notice some improvements but no MPG as others have stated and i dont have my foot in it. Also have noticed from time to time rough idle. Kelley anyone????????????

 

I have already responded to his issue on the phone.

The I5 is prone to a rough idle just by design. We do a couple things to help the idle smooth out, but it doesn't always go away completely.

As far as MPG, it greatly depends on the vehicle and the kind of trip you make/how you drive. Most see 1-3mpg increase, but at the very least you won't lose any MPG with the tune.

 

Thanks for the info. As far as the tune goes i am happy with it. When i want my H3 to get up and go it does. Itdefinitelyhas a lot more pep and i would recommend it to all.

Thanks Kelly and PCM.