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code 18 and 88

6K views 8 replies 2 participants last post by  89F150 
#1 ·
I have the these codes pulling up code 18 and 88. The engine idles low rpm won't climb very high when it's running bad at idle you rev it up and the tach is kind of jumpy. I have changed plugs wires fuel filter ingnition coils fuel pump cleaned the mass air sensor cleaned all the contacts(plugs on dis module on ignition coils ect.) under the hood. Its the 4cly auto trans belt driven fan I just cleaned the K@N I am about to pull my hair out. It started out doing this every once and a while now it does this 95 to 98% of the time. I pulled the codes 18 and 88 with KOEO and my buddy's mechanic pulled the same ones I just don't have the money to let him fix it. The check engine light comes on when it runs bad when it starts running good it goes off. I have replaced the o2 sensor twice and it does not show those symptoms so I do not think that is it. I am tried of blowing money and it's not fixing the problem. Please please HELP. Let me know if I left anything out. I have also had O'rielly check the DIS module and it checked ok. When I cleaned the Mass air sensor I ran a couple or errands it ran fine came back later it was doing same thing. I think this is something really simple I just can't put my hands on it. I am tired of blowing money on parts that is not fixing it. Code 18 means Erratic IDM input to processor/Spuot circuit grounded and code 88 means Loss of Dual plug input control. I also found on another site that code 88 can mean Electronic ignition-IDM,DPI or spout circuit failure. Thank you again for your time in reading this. My name is Scott Ewers and my e-mail address is gixxer750@sbcglobal.net
 
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#3 ·
It really does'nt idle rough just low with no power on take off. I have already checked all the hoses. Is the air idle control apiece you can clean first if so where is it at if it's at the throttlebody there is two sensors up there. Thank you for your help.
 
#6 ·
I took and cleaned the throttle body took it off and cleaned it. I cleaned the IAC let the battery stay disconnected the whole entire time of doing this process. Started it back up 5 seconds later idle drops check engine light comes on.I unplug the IAC while its running runs just a little bit rougher. I found what I think is the spout connector I unplug it and it runs just a little rougher you notice it more when you plug the jumper in than when you pull it out. I checked for continuity with jumper in checked ok. I took my meter put the red on +battery then put ground lead on pink wire on top plug of DIS module that is what I have been told to do. With the truck at idle it read 2.500 to 2.603 volts you start to give it gas it jumps to 1.25 volts up to about 7.89 volts that's about where I stop revving it. I install remote starts car alarms for a living this looks to be the tach wire from the DIS module. When you check for tach signal it should be between 1 to 6 volts mine is at about 1/4 of a volt. Also the sound my truck makes while running take in mind that it has glass packs or cherry bomb one of those not for sure with high performance cat. They have 3 to 5 thousand miles on that exhaust but while its running bad it makes a putt putt putt putt sound. I'm thinking about taking the DIS module off and having O'rielly check it out again because now my truck seems to be running like this all the time. It started off doing this once in a week to 2 week period. Sorry this is so long your help is been greatly appreciated.
 
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