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95 GC LTD Miss at speed


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rcarraher
07-06-2009, 10:12 PM
I have a 1995 Crand Cherokke LTD 5.2L. a couple months ago it started missing at over 50 mph, the it would die at speed, had Codes 11,12 and on the forum here I decided it was the Crank Position Sensor, even tho' this had been replaced by a mechanic 2 years ago. Finally got it changed, which was a bear, and no more dying! Hooray...not quite. Then it would have a miss at idle and sometimes die and leave the Check Engine Light on until it was turned off and restarted, and I got a Code 12, 13 indicatiing the MAP Sensor. The voltages were wrong on the sensor, so I changed it out. Now it idles like a dream and runs fine until around 50 mph, then it has an intermittent miss. No codes or other hints. It has a new distributor cap and wires, new rotor, new air cleaner, new fuel filter, fuel pump was replaced about 3 years ago(maybe 20K miles). I've checked for a vacuum leak but haven't found one so far. I've cleaned the throttle body and checked the TPS for proper voltages. Any ideas?

rcarraher
07-07-2009, 07:01 PM
Okay, I started getting a Code 24 indicating the TPS which I found strange since the voltages are as stated in the manula. So, I took the TPS off today, checked it for smooth operation, and put it on an ohm meter. It checked good (from appx 4K ohms closed to 1K fully open with a smooth transition. I also ohmed out some of the wiring from the TPS, MAP sensor etc... back to the PCM, all fine. Also ohmed out the coil, all fine. Pulled the PCM Connector and cleaned all the contact and found a pinched wire which goes to the coil. Cut out the chrushed part and soldered it back together and sealed it in shrink tubing. Car starts fine, no more code 24. I haven't ran it above 50 yet, but I took it down the street just to "feel" it. Ran great. Got it back to the driveway and checked for any codes. Had a code 12 (batteries been disconnected in last 50 starts). Also got a code 42, ASD Relay! So I disconnected the battery again to clear the code thinking maybe it was erronious. Checked the MIL lights and 42 was gone, just the code 12. Started it up, ran it for awhile and checked the codes again. 42 was back. So I pulled the connector to the PCM and checked for pinched wires and ohmed out all the ones for the ASD and Fuel Pump. No problem. Pulling the connector cleared the PCM again, but as soon as I started it, let it warm up a few minutes, shut it down the 42 was back. In the past month I have replaced the CPS (Code 11 the MAP Sensor (code 13 cleared) Cleared the TPS code today, apparently. and now have a ASD code? Any help?

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