I have a 1988 325 (auto trans) with 120k miles that recently started to miss - at speed and idle, cold and warm. It does start immediately and idles well and, when working properly, runs up smoothly. Lately though it has been missing so bad I cannot drive it. While testing things tonight while idling (warm) it quit.
Compression test (before this started to happen) was good. Vacuum is OK - 18-19 and steady - maybe oscillating between them some. I temporarly taped off some hose fittings to seal the connections and was able to maintain 19. When I try to wiggle the vacuum hoses I do not clearly get it to fail - it can be difficult to tell as it is now missing intermittantly but often. I am not getting a check engine light during any of the missing. Having a vacuum guage while testing shows a sharp drop when it stumbles but it appears that this happens when or after it stumbles and not before.
I recently replaced the plugs - current ones are tan in color - and the distributor cap and rotor; I have not changed the wires. I thought the fuel pump may be a problem but when I pinch off the fuel hose, the engine slowly dies off - not the immediate stumble I am getting. I can listen to the pump near the fuel tank and thing I hear it stumble as the engine stumbles - though it is difficult to tell exactly (like the vacuum hose check). The coil tests OK but at this point I am stumped. So any advice would be appreciated !
Compression test (before this started to happen) was good. Vacuum is OK - 18-19 and steady - maybe oscillating between them some. I temporarly taped off some hose fittings to seal the connections and was able to maintain 19. When I try to wiggle the vacuum hoses I do not clearly get it to fail - it can be difficult to tell as it is now missing intermittantly but often. I am not getting a check engine light during any of the missing. Having a vacuum guage while testing shows a sharp drop when it stumbles but it appears that this happens when or after it stumbles and not before.
I recently replaced the plugs - current ones are tan in color - and the distributor cap and rotor; I have not changed the wires. I thought the fuel pump may be a problem but when I pinch off the fuel hose, the engine slowly dies off - not the immediate stumble I am getting. I can listen to the pump near the fuel tank and thing I hear it stumble as the engine stumbles - though it is difficult to tell exactly (like the vacuum hose check). The coil tests OK but at this point I am stumped. So any advice would be appreciated !
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