For 1990-2009 cars

Definition: Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. The exhaust has a steady spitting sound at idle or low speed.

• | Using Scan tool, check for a misfiring cylinder.

• | Check secondary voltage components for corrosion of EI module coil towers and spark boot ends. Check secondary voltage using a spark plug tester and jumper wires.

• | Check spark plugs for cracks, broken insulator or improper gap.

• | Check wires for chafes or cuts.

• | Check for low fuel pressure and fuel quality.

• | Perform injector balance test to test for clogged injector(s).

• | Check for proper valve timing, broken valve springs or sticking valves. Perform Compression test.