Integrity says it all for this shop. We were passing through Cheyenne pulling a fifth wheel and had been dealing with emission problems while headed south from Montana. We pulled into Mr. Diesel at 7:30 am and were back on the road at 7:45am. They scanned our check engine light, deleted the code, assured us we were safe to continue on our trip and charged us nothing. They did it all with an amazing attitude of service. We can't say enough good about them. We had two different Dodge dealers tell us it would be at least a week before they could even look at our truck. - Dick R. (5 star review on Google)