RPMs fall off

"Twin 454 XLi 1998. Been havin

"Twin 454 XLi 1998. Been having an issue recently where when I first take off there is no issue with RPMs. But if I come off plane and putts around a bit and try to get back on plane, the port engine RPMs fall off dramatically around 2200 RPMs to almost idle RPM. If I back off just a tad on the throttle, the RPMs come back up. After a couple of minutes of trying though, she'll finally come up to speed. Once I get pass that magic 2200-2500 RPM, she runs fine.

I do not think it is gas, because it runs fine until I come off plane. I do not think it a filter because again she does fine until I come off plane. Could it be a timing, engine advance thing? It is however very dangerous in this state because as I bring her up, the stbd engine runs fine and she veers dangerously to port as the port engine RPMs roll off.

Ideas?
David"

When was the last time she got

When was the last time she got distributor caps? Have you looked inside of them?

Do you know which distributors are installed?

"I replaced the caps before th

"I replaced the caps before the 2008 season. I have not looked at them recently but will look at them this weekend. As for as the distributors go, I have to assume they are original as most of the components on the engine are.

David"

"I'd guess they are the De

"I'd guess they are the Delco EST types, with a separate coil. If so, the timing advance is built into the module and is controlled by the computer....maybe its time for the scan tool and see if that finds a sensor output out of tolerance."

"Looked at the distributor cap

"Looked at the distributor caps and they appear fine. Would it behoove me start moving parts around between the engines (Computer, Coil, distributor)? Could it be an intermittent fuel pump issue?

Can you recommend a scan tool or is this something that only a Crusader engine guy would have?

David"

"Fuel pumps on the injected sy

"Fuel pumps on the injected systems usually work or don't. a fuel pressure measurement will tell for sure. The gauges are relatively cheap and some of the chain auto stores loan/rent them.

If you start the parts swap approach, be methodical and take good notes...I've seen many 'tail chasing' episodes that weren't productive.

As far as scan tools, the best ones I've seen are made by RINDA. If you have any doubts, their tech support group is pretty good. If you're gonna make the investment, get one that provides the real-time sensor readouts."

Puzzle is finally solved. Hard to believe I started this 3 years ago. Two years ago, the issue got worse: Can come up on plane once, but if I have to come down for any reason, I'll never get back on plane. When I try to get back on plane, at ~2200 RPM (about the time the second injector kicks in on the 454 XLi), the port engine falls over. I tap the throttle down and she catches up and goes back to 2000 RPMs. After multiple tries, she falls over at ~2200 every time. But if I shut her down for an hour or so, she'll do fine until I try to come up on plane a second time after the rest. It was this sporadic running that had me scratching my head; how could it be a fuel issue if it always works once. Last year I never ran fast and it was therefore never an issue, but this year I've had to run fast a few times and the problem is still there. My mechanic informed me that before I spend hundreds if not "B.O.A.T" dollars with them, try the 115 micron pancake filter. Damn if it didn't work. Crazy puzzle is finally solved. He also said that Crusader does not even use the 85 micron filter any more. I clean the filter at least twice a year, and could see through it, but I guess it wasn't enough. Could also be the pump is old and worn as she has 1025 hours on her.