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I’ve had my truck for a while now and love it. The truck is a 2004 5.4 completely stock mechanically other than a cold air intake and runs great NORMALLY. Lately I’ve been having a problem where when I accelerate from a stop or under 20mph the engine just falls on its face. If the truck has shifted past 2nd gear or past 20mph and I accelerate it gets up and goes. I was thinking one of the catalytic converter might be bad? I hope anyway. I figure if there’s a 5.4 genius on here somewhere it might save me a lot of money and work. Thanks ahead of time 🙏🏼

 

Codes? Have someone check the fuel short term and long term. Just wild guessing, maybe a vacuum leak?

 

Muffler shops can check the cats for blockage.