Hydrolock avoided!!

[Ricky-D]

Makes no difference which ECM you pick, all are interchangeable.

The Interstate module has a different spark advance program but that will not impinge your use.

Most all ECM's you will find will be Standard's since the present practice is to change out to the Interstate ECM's for a performance upgrade if that is at all possible.

***

[Scott from FL, now in Maine]

Thanks Ricky-D. ECM ordered used from Pinwall. Guess I am in holding on further work till then.

[Patrick]

The ECMs will interchange.. The IS unit has a different advance curve than the the Std/tour models..  Many fellas have installed the IS unit on their Std/tour.. Is your ECM an original or aftermarket ??  The aftermarkets have had issues but the originals have been pretty troublefree.. Anything 14yrs old can certainly fail or have pin corrosion trouble which could cause some strange problems I guess.. I can't imagine different timing changes for different cylinders though.. There was one recent runability problem which turned out to be a defective coolant temp switch,, but,, that affects the 'whole' engine operation not just selective cylinders.. It'll be interesting to see what you find.. I'm stubborn,, the electrical systems are so reliable I'm still thinking it fuel related.. If I weren't already a drinking man,, your problem would make me one..

[Scott from FL, now in Maine]

  She runs!!!!!!! Problem is fixed!!! My only reservation is I have no idea what the trouble was!!! I replaced the ECM but it made no difference. So I resigned myself to pulling the carb bank again. Yesterday I pulled it and opened and checked all the floats, screens in the carbs, and all the jets. I also checked the fuel rail and all the hoses. I reassembled most of it last night and finished this am. Fired it up and she is running once again!! The idle is a bit rough at the moment, but I am sure it just needs a resynch after the work that was done. I never found ANYTHING wrong. Everything looked pristine just the way it did after the carb rebuild.
But something had to be wrong in the fuel delivery system because the trouble is now gone. Patrick it seems you were right all along!  Thanks so much to all on the board who responded, your advise and support really helped me thru this weird trouble.

[Rocketman]

Great to hear. 
Whenever you pull something apart, and put it back together again just he way you found it, but something has changed in how it operates, then there was something subtle that you did that you didn't realize.  Perhaps you dislodged something. 
Whatever it was, I'm glad it's working now.

Mark

[lljjmm]

Had a similar situation,  run like a pig on the road, stunt like gas, idled and run rough. Took the tank off , rinsed it out , changed the vaccumm lines, changed plugs (old plugs looked good), changed the added fuel filter, made sure fuel lines had downward flow to carbs from tank, made sure no kinks in lines.  Started right up and runs good ever since.