1995 454 mag with engine miss
 

I have been dealing with a engine that is misssing or has a fuel problem I think. I have completly drained the fuel tank, checked grounds, new plugs and wires, checked alt to make sure im getting correct voltage, ran fuel injection cleaner... I was wondering if there was a inline fuel filter on this engine as I cannot find one other than the fuel/water seperator. The engine sounds fine on the muffs in the driveway. it starts and runs fine at idle but when Im driving the boat on the lake it does not sound right at all ( kind of muffled sounding) and the power is not there. I cannot get the speed I was getting before. I lost about 4-5 mph!! Im thinking I might have a fuel or ignition problem. What else should I be checking???

Are the rpm's down along with the speed

Miss
 

How old are the plug wires? If you have a faulty secondary ignition system it will deteriate under load. Run good with the muffs on it but under load with the ignition system under load with the compression and trying to fire the plugs the wires will break down and you will get the miss you have been incountering.

An old trick also is wait untill pictch black raise the hood start it up and a lot of times if the outer insulation is bad on the wires you will see little traces of spark comming out of the wires grounding against the engine block. I have seen wires so bad that it looks like Detroit city under the hood.
Not saying this is it mind you just somthing to consider.

Also check the inside of your cap unless you have a D.I.S. and see if there is any traces of tracking or miss firing in the cap. Check your plugs also . Check there grey on the eletrodes is there is a plug that is wet or a large fuel deposits on it then you found the cylinder that is misfiring.

Hope this helps

I dont think they are... I will check tomarrow to verify this forsure.

I changed plug wires and plugs and it ran the same.

Change the dist cap and rotor.

Also try the magnetic pickup in the distributor. Mine caused a miss that I chased for a long time. Turned out to be the pickup. Keep us posted.

If it sounds like it is bogging down or not making correct power, typically it is a fuel delivery issue. A miss it usually spark related. I had a similar issue with my boat and my inline fuel filter was clogged. Once I cleaned it, it ran perfect, but this was on a carb motor. But I would expect that there has to be some sort of fuel filter somewhere. Just follow the line from the tank, if possible to the motor and see if there is one somewhere inline.

Hey Sam, welcome to OSO. I see you are from Columbus, where do you boat?

Sorry to de-rail your thread Z06...

thanks to everyone for the help! First thing this morning I went to the dealer and picked up a fuel filter, cap& rotor. I installed these items and went out to the lake to see if any of this would cure my problem...it did!!! Speed back and the motor sounds good again.