cel on RPM'S droped by half

[91rangeryder]

Im new to the forum just bought my ranger 2 weeks ago. This problem happened to me rite after i bought it. Then it went away. Now more times than not the check engine lite comes on and the rpms drope by half. I know someone has posted this problem recently but there post didnt help me. Its a 91 2.3 ranger with a 5spd by the way. The pass side coil isnt putting out spark i checked the coil and its fine. I installed another coil i knew worked and had the same problem. I checked all grounds and wires. Its puttimg out a code 18 31 88 off mem and a 18 98 off KOER. I was also wondering what that condensor looking thing was thats gets bolted on with the coil I thought that may be it ? Any input would be a huge help thanks

 

[Sevensecondsuv]

The "condensor thing" is the radio interference prevention capacitor. It cannot cause the problems you describe.

If the coil checks out fine, I suspect faulty wiring. Check all wiring associated with that coil pack for nicks, cuts, etc. Also check all the engine grounds.

 

[91rangeryder]

Thanks for the tip im new to the distributer less ignition systems. I checked all wires in the system short of being dirty the all looked fine. My ground clamp on the battery was a little messed up im gonna buy a new one today. Do you think that could have something to do with it ? Iv seen vehicles do weird things when having bad grounds.

 

[Earl43P]

If 91 is the same as 93, I can send you "stuff".
PM me your e-mail address.

I think you have a bad crank sensor.

 

[Sevensecondsuv]

91 is the same as 93.

But the fact that his tach fell by half indicates that one side of the ignition system isn't working. A bad crank trigger will cause the whole ignition system to fail, not just one side.

 

[91rangeryder]

I replace my ground clamp. I checked and cleaned all the grounds to the body. All the wires look good in the system. I thought it could be the DIS but I was told it would either work or not work . Im stumped. Is there anything else im forgetting ?

 

[Sevensecondsuv]

Have the DIS module tested. Autozone, Advance auto parts, etc will do it for free.

 

[91rangeryder]

I'm going to pull the dist off today and get it tested I'll post the results, and possibly ask for more Help thanks.