'94 945T

I've been chasing this gremlin for over a year. When I think I have found it, it always reappears within a few days. Here is the symptom. It is most prominent after a deceleration but not always. Upon acceleration there will be a slight to very pronounced stumble. The tach drops and there is an associated loss of voltage at the coil. I am convinced it is electrical (there was a bad FPRly causing the in-tank pump not to operate but that has since been replaced with no change in the stumble). It seems to be more apparent in high ambient heat & when the engine is warm, on a cold morning it rarely acts up (but sometimes it will). It manifests with medium to heavy acceleration, a light foot usually has no stumble. At speed there is no stumble but, on occasion, hard acceleration when moving can result in a stumble.

I have cleaned all the electrical connectors (both cable connectors & component connectors) in the engine compartment with deoxidizer spray and have replaced the FPRly, RadioSuprRly, power stage, IACV, throttle switch, MAF & CPS. I've cleaned all the grounds I can find (engine & body/fender) About all I haven't poked around is the main computer.

Any ideas?
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1999 E320 1994 F150 (awaiting a new engine) 1989 560 SL 1994 945T (daughter's) 1986 242Ti (awaiting a B230FT transplant) 1968 GT500KR (under slow restoration) 2007 HD Nightster (son's ride)