I've had this car for 4 years no major issues. It sat for a week, after a couple of miles stabilitrak lit up and the car started missing. Turned around to limp home and it straightened out for a mile then started missing again with raw gas making it to the muffler and igniting. I pulled these codes. Since the problem comes and goes quickly it seems electrical. I wouldn't think an O2 sensor would make it run this poorly. I replaced the front one on the driver's side a year ago. Any thoughts where to look first?
2007 Tahoe sudden P0300 P0154 P0352 P0354 P0356 P0358
- Thread starter Spin
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Roger08LTZ
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Did you solve this issue? I'm having a very similar issue, but my codes are on the left bank and yours are on the right bank. Same symptoms ran perfect one second, then stalled. I was able to restart and limp home. Suddenly power seemed fully restored, but shortly I was misfiring again. Any Ideas? I have codes: P0134, p0300, p0351, p0353, p0355, P0357, P1133.
Thanks
I'd focus on the ignition coil wiring on the driver's side. You may just have a main connector that is, well, not making a good connection. Having all of the cylinders on that bank with a common code (P035x) seems a bit coincidental. Follow the coil wiring back to a common place and check and clean connections.
Roger08LTZ
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I finally got this car in the garage for a good look. I've very closely inspected the wiring and there is no corosion or damaged wires. I buzzed all of the Injector harness wires with a multi meter and all are good conductively. I also bench tested the coils through the injector harness with a bench power supply powering with 12 Volys, but triggering with 5 Volts. One coil does seem weak, but I was loosing the entire bank. I doubt one bad coil could take down the whole bank and it does fire, just much weaker than the other coils. So I'm certian the injector harness is good and 3 coils have really good spark. Next I need to test the PCM side. The harness appears OK and according to the wiring diagram the Left & right bank share the same ground, so it shoulden't be a bad ground. I do see on the wiring diagram there are seperate 5 volt supplies for the left and right bank so, I'm thinking a bad PCM. I'm going to keep testing before I order one. I have tested the PCM side for good grounds and good 12v, but I havent had a chance to put the scope on it to look at the 5 volt signal wires.
I'm new to the LS style engine, Am I missing somethig? Can you/How do you test the resistance of these 4 wire coils?
I do need to replace at least 1 coil, go OEM AC Delco? or are there any good aftermarket coils?
All of the coils look origional and the car is 14 years old with 190K miles on it. Should they ALL be replaced? I am planning on keepin this Tahoe for a long time. I've been through this before on the Ford 4.6 COP coils and it seems they all start failing shortly after the first one fails, so you should just replace them all at once if you care about the car. Not sure if it's the same with this style coil.
Thanks!
I'm new to the LS style engine, Am I missing somethig? Can you/How do you test the resistance of these 4 wire coils?
I do need to replace at least 1 coil, go OEM AC Delco? or are there any good aftermarket coils?
All of the coils look origional and the car is 14 years old with 190K miles on it. Should they ALL be replaced? I am planning on keepin this Tahoe for a long time. I've been through this before on the Ford 4.6 COP coils and it seems they all start failing shortly after the first one fails, so you should just replace them all at once if you care about the car. Not sure if it's the same with this style coil.
Thanks!
Solid diagnosis. I concur with the PCM hypothesis.
Coil failures are rare on these. Lots of folks running around with 400K+ on 'em. Not like other cars in that way.
Hopefully, when you figure this problem out, you do a better job than @Spin and come back with results of what it was. So many times, people join for their own problems and then crickets.
Roger08LTZ
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The new PCM is installed, still same issue. No fire on the left bank. confirmed by touching the exhaust manifold, left side cold, right side hot. Scan tool shows good 5 Volt reference signals 1 & 2. I unplugged and tested the engine side of the coil harness, I am seeing 5 volt signal pulses and a good 12 volt ignition and grounds seem good. I haven't tested the fuel injectors at all as I smell raw fuel. Anything else that could take down the left bank? I do have a scan tool, but it's new to me so I'm not sure what to check with it.
Thanks!
The only good news is I have a spare car.
Have you also tested the right side signals and grounds to see what you have there compared to the left side?
OK, I can’t help but wonder if the problem is a connector that’s not passing along enough power to run the coils under load. Did you hit all of the connectors with electrical contact cleaner? Did you remove, clean, and reconnect the primary ignition ground?
Did you check each connection and make sure a pin is not being pushed out of the connector when plugging it in?
Roger08LTZ
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The connectors look perfect, contacts are clean, but yet it does feel like the issue is in the connector issue. I'll test under load tomorrow night.
Thanks!
They can look perfect and be clean but still can push a spade pin backwards out of the connector when you push them together.
Roger08LTZ
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99% sure the issue is the wire at ground point G102. Under load the voltage at the coil was 1-2 volts lower than the battery. When I inject ground to the wire I get spark. I cleaned and reinstalled the wire at ground point G102 and the problem got worse. The eyelet connection to the wire seemed weak and pulled off with not too much effort. I need to crimp a new eyelet on and I bet the problem will go away. It's difficult to access it though, nothing is ever easy!
That is why, especially on these ground(s) problems, when you locate and disassemble them and repair them, make sure you do it once and do it right. I was hoping that a connection problem, like I described above, would be a connector that controlled the entire side of the engine. That ground is a good find. Make sure, if you fix it with this ground repair, that you pat yourself on your back and have an ice cold beer. Lots of people would have just given up. Think of the diagnostic time $ you saved if this works.
Roger08LTZ
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The ground wire fixed it. I haven't road tested it yet, but it's idling on all 8 with no misfire codes
Happy days are here again! 
Roger08LTZ
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It's not quite fixed. It's running fine, but as I was afraid, the money light came on with the dreaded P0420 Catalyst system low efficiency bank 1. I assume the raw fuel hitting the Cat killed it. Any chance this thing will burn itself clean? A new GM cat is over $1,000. Rock auto has some for about $400. Any experience with aftermarket cats?
I have had luck with Walker exhaust systems. I would use OE though if it was me but it is your money. How old are the sensors?
It depends on whether the honeycomb media melted or if the coating just got saturated. You might try a bottle of Cataclean before dropping the money on a new cat.
I haven't used an aftermarket cat for one of these trucks, but I did install one from Rock Auto (AP/Eastern) in my LR2 about 20K ago and it's been fine.
