October 30: LEMON manuals on a temporary server, it is slow and having issues, download the manuals you need! Later in November we will switch back to the fast server.

Diagnosing Fuel Quality Problems: Symptoms

A fuel quality problem may be indicated by the following driveability symptoms:

Spark knock/detonation
Hard cold start and garage stalls
Poor cold performance
Tip-in hesitation, sag, or stumble (momentary lack of response during initial acceleration)
Surges and/or chuggles
Lack of power, sluggish, or spongy
Cut out or misses
Rough/unstable idle (intake or exhaust valve deposits)