7.4 TBI Looses rpms after running for awhile

[capt hook]

I have a 1995 Tiara all tuned up new filters and no codes on scan tool. After running at 3200 rpm I start to slowly drop off and end up at about 2400 rpm. Never stalls no crazy spurts just will not get back to full rpm until it cools off then does it again. One tank and other motor runs fine. Also no antisyphon valves. 7.4tbi 800 hrs. Please help.

 

[kimosammy]

Check fuel pressure. I have a couple 454TBI's and the fuel pressure reads 21psi. The reason I know is one engine would get going and then sputter to only a high idle..my obisk filter (Pancake filter) was clogged.

 

[Colonnas marine services]

Check fuel pressure as problem accures? If normal 20 psi then check spark strenth must jump gap 3/4 inch all the time be careful.