Question about 1999 GMC Jimmy
I just bought this truck about 2 months ago. Just recently the SES
light came on. Had it read. Turns out to be a P1345 code. I have
replaced both the cam and crank sensors. Since then when first
accelerating at very low rpm's I can feel the misfire. Or at high
speeds(70-75) around 2000rpms the same misfire happens. I got off the
highway when this happened. Had the truck scanned again. Same code
P1345 and a misfire code. I have recently(past 2weeks) changed the
plugs wires cap and rotor(same time as the cam sensor).
With the recent plugs wires cap rotor and cam sensor the truck ran fine for a couple of days then the P1345 came back. The truck ran fine. Had the scan tool hooked up and it cycled and no misfires. About 4 days later the light came back on again(each time it was cleared). Scanned again and it was not cycling. Changed the crank sensor. Now cycled a random misfire after the truck had been running about 20min, but then the computer cleared the misfire(no code thrown). Drove the truck around and about 3 hours later when I started the truck the SES came back on. Drove it around and could feel it misfiring again but only at low speeds(didnt want to push it on the highway).
I need help because this is starting to **** me off.
I did read online that when I replaced the cap rotor and cam sensor that the distributor possibly might be off a bit and could cause this.
I did get all of the repair reciepts when I bought the truck and one of them was the distributor was replaced through a recall.
Well that sounds like a tough one , But here is a site worth checking out . Several mechanics use this it to help out people like your self that are frustrated and are getting P #$%$# off ! Good luck
Posted on Mar 09, 2009
I just fixed my problem with all the same symptoms!!!! It took me 3 years of dealing with this problem with 4 different dealers and shops all taking their opinions on it... It's the distributor gear! Pull the distributor and look at the cam gear, if it is worn then the cam position sensor is not getting an accurate read of where the engine is at. Also u should be able to shake the distributor up and down and hear a click sound, that's because the bearings in the plastic shaft are SHOT! A new distributor from summit racing will fix your problems and only costs 150. Just be sure u know how to align the motor to TDC and u are good!
Posted on Aug 01, 2012
I've seen this problem many times. Replacing the gear on the bottom of the distributor has fixed it every time.
Posted on Mar 31, 2012
Hello I'm 28 mastertech,I'be seen this a lot on 4.3 v6 and the v8 5.7. The distrubur shaft is warn out,it's plastic you know causing to much play,or was installed wrong. You top dead center engine put distrubur in make sure if 6, there is a 6 on distrubur point to 6 4.3 if 8 point to 8 clear codes should not come back.1800Rick@gmail.com
Posted on Jan 03, 2012
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