I have the stock ignition and the computer has not been reprogrammed. When I put the new plugs in I gapped them to .030. Yes, I have a boost referenced fuel pressure regulator. Has anyone had problems with their regulators?

The other day, I did happen to check the intercooler. It was leaking. When I pulled it off, there was about 5 oz. of water inside of it. I also pressure tested it to confirm that the core leaked and it failed. I replaced the intercooler and it did not fix the problem, but I can feel the difference up to 4,000 RPM.

This weekend I will do a compression test.

Procharger regulator is junk. I have one just reconditioned from Bell Engineering, if you're interested. click here

Upgraded my ECM and don't use it anymore.

Thats how i lost my engine. Busted intercoller = hydrolocked and bent rod, crush piston. In the drive way on hose!

Agreed. I replaced my boost reference regulator and the fuel pump.

I didn't find anything when I did the compression test. Everything looked good there. My next step will be to replace cap and wires and MAP sensor. I will check out the fuel pump next time I go to the lake...

Was it running good and then started to have the problem, or was this just worked on, assembled/reassembled or anything like that?
The reason I ask is, are we trying to trouble shoot a newly developed problem, or newly install problem.

I helped a friend install a Procharger on a 454MPI and we started it on the hose in the shop, sounded good and idled perfect. Towed it to the lake and it didn't sound right. Ran it up and didn't have as much power as it should and couldn't get it over about 4000. Scratched our heads for about 45 minutes at the dock looking for anything strange and checking timing. Reach under plenum to check for loose hoses and pulled out an injector plug. It must have not been locked on all the way, and popped off while towing. We hauled it back to the shop and pulled the plenum, reconnected the injector plug, and put the plenum back on. Dropped it in and ran like a raped ape, compaired to before.
Not that this is your problem, but 1 dead cylinder can cause your problem.

This is a newly developed problem. It didn't do it before...

I changed the distributor cap, rotor and plug wires and it runs better but it did not solve the problem. The cap and rotor probably looked worse than I have ever seen any before but it was the first time that I have changed them since I have owned the boat. I am starting to think that I might need to get an MSD ignition on this thing...

whats your fuel pressure at? and have you checked your injectors for crap in the tops of them. had the same problem with mine read the post on here about mpi owner fyi.

After replacing the TPS, MAP and IAT sensors, the boat has run much better. It no longer cuts out at 4,000 RPM! I appreciate everyones input on this issue.