P0300 Pontiac - my engine light flashes only at 80 mph

Question

My engine light flashes at around 80mph, when speed is reduced the engine light goes off. sometimes the engine light stays on and gives a p0300 code. I took it to get checked out and the mechanic said he did a major tune up on it. including spark plugs, wires and one coil pack. Since then i've replaced the other two coil packs and the ignition control module. None of this solved the problem.

Answer 1

Hi there,

Here is a list of possible causes for a misfire.

P0300 PONTIAC - Cylinder Misfire Detected Random Cylinders

Read more: https://www.autocodes.com/p0300_pontiac.html