Cold compression all cylinders about 175. New plugs and coils check good. starts good but when warm cylinder four drops out.
Apr 21, 2022 at 11:32 PM
Engine misfire when warm
2000 PONTIAC GRAND AM
DOUG CARNAHAN
- MEMBER
- 1 POST
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Doug,
When this happens, have you checked to see if the cylinder has lost spark or if the injector has lost a pulse signal?
If you haven't, that is what needs to be done. What I suspect is happening is this. When the engine heats up, so does the ignition coil housing. Heat causes expansion when it comes to metal. I am thinking that the connection between the coil and coil housing for cylinder 4 is being lost. Recheck where they are connected to see if there is any excessive play or clearance.
See pic 1 below.
Let me know what you find.
Joe
See pic below.
When this happens, have you checked to see if the cylinder has lost spark or if the injector has lost a pulse signal?
If you haven't, that is what needs to be done. What I suspect is happening is this. When the engine heats up, so does the ignition coil housing. Heat causes expansion when it comes to metal. I am thinking that the connection between the coil and coil housing for cylinder 4 is being lost. Recheck where they are connected to see if there is any excessive play or clearance.
See pic 1 below.
Let me know what you find.
Joe
See pic below.
Image (Click to enlarge)
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Apr 22, 2022 at 12:45 PM
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