Q: Truck won't accelerate past 35mph

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Suddenly for no reason my truck won't accelerate over 35mph it's a 4wd 4spd tranny with a 350. She accelerates through 1st 2nd and 3rd without any issue up to 35. When I shift to 4th she just stays at 35 no matter how much gas I give. How do I fix this issue?

Hi There, This may be a sign of a clogged catalytic converter. The catalytic converter converts toxic exhaust gases into less harmful pollutants that are suitable to be expelled into the atmosphere. When this is clogged, this causes these gases to be backed up into the exhaust system not allowing the engine to breathe properly. When this happens, the engine is forced to work much harder to expel these gases. This often results in the engine bogging down, hesitating, shaking and causing very poor fuel economy. This should also cause a check engine light to come on as the O2 sensors should be reading the incorrect amounts of oxygen in the exhaust gases if this is your problem. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your catalytic converter.

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