225 EFi low rpm rough running Help!!!

magnoman

Petty Officer 2nd Class
Joined
Jun 19, 2007
Messages
146
My 98 225 EFI is running rough the whole boat shakes at 900-1300 rpm. There is no problem starting, running at cruising speed.This all seemed to start happening when I took off the O2 sensor to check the condition of the o2 rod that goes into the cyl head. I know they are prone to getting clogged and I check mine a few times a season. after that it started to run rough? I checked the O2 sensor and the wires seemed to be pinched and it was origanal 98 so I bought a new one $250! and it still runs rough at low rpm?
any ideas anyone? I did put in the fuel additive for the ethanol problems that so many people seem to be having but I have a plastic gas tank in my boat and never had any troubles with fuel...
 
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