I wanted to e-mail and thank you for your engine oil treatment. My truck was shuddering in cold weather and when it got windy. People recommended wheel alignments. I did that and it still continued. I put top quality gas in and it still shuddered. I decided to have the oil changed. I usually do it myself but with the cold weather I had someone else do it. I had them put quarts in and I added one quart of your oil stabilizer. The truck cruises at seventy without any problems. I have been chasing this problem for awhile. I was going to trade but now that your oil has solved the problem, I'll keep her.

By the way, next week my truck will celebrate her 14th birthday and will have 365,000 miles on her.

Thanks once again,

Bill Dalbey