95 merc 225 efi won't run off idle

[crankin4bass]

I got stranded on the river yesterday when my engine did not want to run when I would stick it into gear and try to go. It has had a light mid range miss for a little while but yesterday I drove it a few miles and shut it off. When I went to leave it acted like it was'nt getting enough fuel to run in gear but it would start and idle. I had to be towed back to the launch.
Some of the preliminary testing I have done so far are as follows:
1) Fuel filter and fuel were put in a week ago and boat ran ok
2) Fuel pressure is 39 psi
3) As far as I can tell the TPS, IAT, and coolant sensors test ok according to the info that I have. I have not yet checked the Map sensor.
4) Compression is good in all cylinders.
I would sure appreciate any insight on this problem.
Thanks

 

[CharlieB]

Re: 95 merc 225 efi won't run off idle

You checked important items but you did not mention if you checked SPARK on each cyl using a 7/16 inch gapped tester.

One or two dead cyls will still seem to idle OK, and run horribly or outright die once placed in gear.