5.7L EFI problems

[brooksdonald]

I have a 1999 5.7L EFI w/ Bravo III. Engine runs fine for about first 15 minutes and then starts missing around 4000 rpm. Temperature gauge fluctuates more than normal (160-190F). Any thoughts on what might be causing this? I replaced the thermostat and temperature sensors. First time user - thanks for any help.

 

[Reel Poor]

Re: 5.7L EFI problems

Do you have the engine serial number.

190 is to hot. When was the last time you changed the water pump impeller and checked the manifolds/risers.

 

[brooksdonald]

Re: 5.7L EFI problems

Engine serial # is OL337164. I'm having the impeller changed and manifolds/risers checked today. Hopefully, not too much damage has been done to the engine. Thanks.

 

[Reel Poor]

Re: 5.7L EFI problems

Also when was the last time it was tuned up, plugs, wires, cap, rotor, and fuel filter?

 

[Don S]

Re: 5.7L EFI problems

Are you raw water cooled, or do you have a heat exchanger with anti freeze?
Are you in fresh or salt water?