Table of Contents

11.4.1 Engine Running on One Cylinder

Q: Engine sounds like it's running on one cylinder.

This could be a spark plug issue or the result of a lean condition on a single cylinder.

Try increasing the lower RPM VEs by 10-15 points on either the front or rear VE tables. Program these changes to the ECU and see if the condition has improved. Some stock exhausts do not provide the rear oxygen sensor with good exhaust sampling, this prevents any automatic adjustments or indicators that would show or fix a problem. Having one cylinder too lean often leads to the engine sounding like it is running on one cylinder (like a tractor) at idle.