About a month ago, I put some Lucas injector cleaner in my truck. A few days later it was very cold. I started up my truck(5.4) and gray smoke started to fill the garage. Once I pulled it out it wasn't as bad, but if I gave it a quick rev the smoke was still there. Now it hasn't done it for a while, and I'm starting to think it was the Lucas. Any suggestions on the smoke or just fuel additives in general?

 

The Lucas really isn't that great of an injector cleaner and is more for UCL. Due to its properties if not fully mixed with gas initially it can settle out a little. I don't know if this explains the gray color but it is possible. As long as you use top tier fuels additives aren't needed and injectors really don't need cleaning. If you use a cheaper gas brand, a good PEA based injector cleaner (Techron or Gumout Regane) is the only proven way to help, but still is not always needed. Many get placebo affects from naphtha and xylene cleaners but they do very little in the way of cleaning.
So it depends what your objective is, if you want a UCL, stick with the Lucas. If you want to clean your injectors, go with a PEA.

 

Gotcha, thanks for the help

 

Hello,
Check the fuel return line - if it's blocked you'll get more smoke. and maybe any problem with any part of engine. i also just changed my motor of engine because of problem. i bought it from here on ebay at very good rates and now it is working very good.