Volvo 240 User Manual page 105

1987 Volvo 240
Condition: Erratic idle (misfiring)
Possible cause
intake system leaking.
Spark plugs, high tension leads or distributor
cap worn (detective)
Worn spark plugs.
Condition: Engine stalls at irregular intervals
Possible cause
Defective wires.
Intake system leaking. Check vacuum hose connections at manifold and auxiliary air valve.
Fuel filter clogged.
pg. 93 Service diagnosis
Condition: Excessive fuel consumption
Possible cause
Fuel lines leaking.
Spark plugs worn Replace plugs.
Condition: Misfiring at highway driving speeed
Possible cause
Spark plugs
fouled.
file:///K|/ownersdocs/1987/1987_240/87240_03c.htm (9 of 11)12/30/2006 7:53:32 AM
Correction
Check wire terminals at: fuel pump, fuse No. 5 and 7, coil, distributor, ignition
switch and relays.
Clean fuel tank filter and replace line fuel filter.
Correction
Check
tightness.
Correction
Drive the vehicle in a lower gear and keep the engine rpm higher for a few miles
in order to remove carbon deposit on the spark plugs. If this procedure is not
effective, clean or replace the spark plug;
Correction
Check hose connections.
Clean distributor cap and leads, check the cap for
cracks. Replace defective or worn parts.
Remove. Clean or replace spark plugs.