Expert: Sean Halliday - 12/2/2007

Question
QUESTION: My son has a 86 jeep commanche pick up. When the engine is warm he loses power. He says there is no catalitic converter in it, and when he is driving you can smell fuel.
Recently replaced is control modular, rotor, rotor cap, spark plug wires, alternator, fuel and air filter and fuel pump.

ANSWER: Whats the mileage?This could be a factor with high miles and possible worn valves or piston rings.The fuel smell must be looked at as its a fire hazard.Hard to say without actually looking at the car as there are so many reasons for a fuel smell.If he fitted all these new parts,i would double check all fuel lines and make sure there is no leak at the engine injection or carb.If the fuel is leaking that will cause the motor to lose power.

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QUESTION: The two spark plugs by the firewall when pulled, had a fuel smell and a glossy appearance compared to other plugs which seem to have a carbon like appearance. The mileage is about 186 thousand. It sounds terrible when it is running. There was no warning to this problem except we do remember smelling fuel, which we noticed after turning it off.

Answer
You have a misfire on these 2 plugs it seems.Do a compression test on the 2 cylinders and check the wires are ok and also the plugs are gapped correctly.The proper plugs for this car would be either autolite or champion,dont use NGK.Or Bosch.The reason it sounds bad is because its misfiring.The valves may be worn and causing the compression to drop too much for the cylinders to fire.They must read approx 100psi.You may as well test all of them.Let me know what you find.