* Restricted Exhaust: This is the most common cause. Clogged catalytic converter(s), a severely rusted or crushed muffler, or a blockage further down the exhaust system will cause excessive back pressure. This forces more heat back into the exhaust components, making them overheat and glow red-hot. A partially blocked system might only show the problem under load (e.g., climbing a hill).
* Lean Fuel Mixture: If the engine is running too lean (too much air, not enough fuel), it burns hotter. This excess heat is transferred to the exhaust system. This could be due to a faulty fuel injector, fuel pump issues, clogged fuel filter, malfunctioning oxygen sensor, or problems with the carburetor (if equipped).
* Ignition Problems: An inefficient ignition system (worn spark plugs, faulty ignition coil, bad distributor cap or rotor) can lead to incomplete combustion. Unburnt fuel entering the exhaust system will burn there, generating significant additional heat.
* Exhaust Leak Before the Catalytic Converter: A leak *before* the catalytic converter allows unburnt fuel and oxygen to mix further down the exhaust, resulting in a secondary combustion in the muffler or tailpipe, leading to intense heat.
* Engine Overheating: While less directly related, a severely overheating engine will inevitably transfer a significant amount of heat to the exhaust system. Check your coolant levels and look for signs of overheating.
What to do:
1. Safety First: Do *not* touch the exhaust system while it's hot. It can cause serious burns.
2. Inspect the Exhaust System: Carefully examine the entire exhaust system for any signs of blockage, rust, damage, or leaks.
3. Check for Engine Overheating: Make sure your cooling system is functioning properly.
4. Address potential fuel mixture and ignition problems: Check and replace spark plugs, wires, the fuel filter, and inspect the other ignition components. A mechanic can perform more in-depth diagnostics to check for lean conditions.
5. Professional Help: If you're not comfortable inspecting and repairing the exhaust yourself, take your truck to a qualified mechanic. A cherry-hot exhaust is a serious issue that needs professional attention. Ignoring it can lead to a fire hazard or further damage to your vehicle.
