4.3 merc t.b.d stalls when warm

[twixter]

I have a 2001 4.3 throttle body injection bravo 2 drive. it stars 1st crank runs fine for a while then starts to sounds like it missing some time it stalls some time it revs up like just started. fixes ive already tried, cap, rotor, electronic sensor in cap, dumped fuel filter gas looks good, tempture sensor, spark plugs. ive even tried to get a mechanic for a feel like im throwing money at it for no reason.. im stumped any body have any ideas or a mechanic that will actually come to northport new york

 

[CaptainMak]

Re: 4.3 merc t.b.d stalls when warm

When did it start doing this ? This season after you de-winterized it or was this an on-going problem ?

"It runs fine for a WHILE". Define "while" . A minute, 3 minutes, after a hard run, when it warms up ?
Is the choke opening up correctly ? Might be your IAC valve going out or the TP Sensor.

 

[Volphin]

Re: 4.3 merc t.b.d stalls when warm

What did the plugs look like?

 

[alldodge]

Re: 4.3 merc t.b.d stalls when warm

I have a 2001 4.3 throttle body injection bravo 2 drive. it stars 1st crank runs fine for a while then starts to sounds like it missing some time it stalls some time it revs up like just started. fixes ive already tried, cap, rotor, electronic sensor in cap, dumped fuel filter gas looks good, tempture sensor, spark plugs. ive even tried to get a mechanic for a feel like im throwing money at it for no reason.. im stumped any body have any ideas or a mechanic that will actually come to northport new york

:welcome: to iboats

Need more info as others have requested, but my first thoughts are either the IAC, IAC muffler or fuel pressure

 

[twixter]

Re: 4.3 merc t.b.d stalls when warm

it runs for roughly 10 minutes untill its warm then statrst missing, pulling the plugs they were fine. this problem started at the end of last season. it will not stall if you bring up rpms but you can feel the miss. i did change the sensor that is in the theromstat housing. when it stall it starts rght back up

 

[solar7647]

Re: 4.3 merc t.b.d stalls when warm

Have you tested it in the dark to see if you can visually see any sparks? I had the exact same issue a few yes back, ended up being a bad plug wire that would start arching once it was hot, the cracks in it would open up and start arching off the block.

 

[achris]

Re: 4.3 merc t.b.d stalls when warm

it would be worth get a scan tool onto the engine to see if there are any error codes set if there are it might point you in the right direction tbi/mpi are often difficult to diagnose without the right tools and software to read what the computer is saying