QuestionMy 82 Spectre with 12K miles is missing, hessitating, and detonating (soft explosions in the exhaust pipe) between 1K and 3.5K RPM. Idle is excellent and stable, as is excelleration and performance above 3.5K. This problem is most notable on a slow take off from a stop sign - the slower the accleration though the 'trouble range' the worse the chugging, coughing and sputtering.
The problem is non rythmic and is less pronounced when the engine is cold. Further, anytime the engine drops into this RPM range, in any gear and you attempt to accelerate back up through the range the problem is prevalent.
Cylinders 1 and 2 have normal looking plugs, while 3 and 4 look somewhat carbon/oil fouled.
Any suggestions on where to look or what may be the problem?
AnswerHi Bill,
Sorry for the delay...down with the Flu.
I suspect the carburetor pilot circuits are partially obstructed by varnishing or the pilot circuit simply needs tuned. Clean or adjust the carbs.
With evidence of oil fouled plugs, perform a cylinder compression and leak-down tests to learn the condition of the engine.
Clean or replace the spark plugs.
Respectfully,
Mark Shively
