My muffler was loud and my check engine lightwas on. I knew the gas cap was okay and neaded to fix the muffler before I hd my car inspected. soI had my muffler system installed and I also had sensors replaced. Last night I picked my car up the light is out I ran it for about 35 miles the truck started dog out and sputter with black smoke. I ran it today It ran good but I am not sure if this is a tempory sense of well being I put dry gas in and used high test

I believe an overly rich fuel mixture causes soot. You might have an injector problem. If the problem persists try running a couple of tanks of fuel system cleaner to clean out the injectors first. Run the tank nearly empty with each fill up to get the best results.

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Sgtsandman's Work in Progress
2011 Ranger XLT, 4X4, 4 door Super Cab. 4.0L, 5 Speed M50D-R1HD, 3.73:1, 8.8" open differential, Jason Pace cap
2019 Ford Ranger STX FX4, Super Crew, 2.3L Ecoboost, 10 speed automatic, 3.73:1 with rear locker, Leer 100XR cap

Thanks for the tip Sgt.Sandman, I will try it