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1996 58 efi wonbt idle

P

p4cruiser

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"I have a 1996 cobalt 220 with

"I have a 1996 cobalt 220 with the 5.8 efi engine. The engine currently idles rough and then stalls. Above 1000 rpms it runs perfect. No problems under load or WOT. I have had it into two dealerships in Salt Lake and they can not find out what is wrong. No codes in the computer. Very frustrating especially trying to pull skiers. Every time you stop and put it in to nueteral it starts to idle rough. The engine will always restart, but you need to put it into gear quickly so that you can increase the rpms to keep it running. Any suggestions would be great. Thanks."
 
Clean your flame arrestor. I&#

Clean your flame arrestor. I've said it a thousand times and this won't be the last- it's the single most neglected thing I have seen on boats and even a lot of dealers don't clean it as well as they should.

Have them check the idle air controller. If you can keep it running at any throttle position above totally closed. it's not getting enough air. It also won't throw a code.
 
"The Flame arrestor has been c

"The Flame arrestor has been cleaned. One dealer thought it was the Idle air controller, but checked it and said it was ok. Maybe I should replace it anyway. Still a mystery, but definitely want to figure it out. Thanks for your help Jim."
 
"Get an itemized list of every

"Get an itemized list of everything they did. If the fuel filter(s) need to be changed and they didn't do that, you can have issues due to slightly low pressure coming down to idle.

Ask how they checked the IAC and find out if they re-parked it. If it stuck a few steps in, it can choke the motor. I don't have any real experience with Ford EFI (it is a Ford, right?- GM motors are 5.7L unless it's one of the new ones, and then it would be a 5.3L, 6.0L or 8.4L) but I can't see why anyone needs to reinvent the wheel just to put a motor in a boat, so my background with GM motors should help. This could be caused by a lot of things but I would start by looking at the battery cable clamps and terminals to make sure they're clean and tight, then go to the ground point on the motor to check the same thing. Then, on to the sensors to make sure the connectors are undamaged and secure.

To be honest, if they only looked for codes and not much further, they need training. There's always a reason for a motor running badly. Could be the fuel quality, a clogged fuel pickup tube, filter or injector, water in the gas, old gas, low compression, bad valves, etc. I don't know the service history of the boat/motor so all I can do is offer suggestions that cover a broad range."
 
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