OldGuyNewJeep
Well-Known Member
- Thread starter
- #1
Question for those of you more familiar with engines than I am.
2016 GMC Yukon XL. Not a Denali, so it’s the smaller V8 (5.1L?) 50k miles.
Anyway, check engine came on. OBD reader showed air/fuel ratio error (my cheap reader didn’t say if it was lean or rich) and cold start rough idle. The latter was evident - start truck in the morning and it was rough for a few seconds, then smoothed out and was fine.
My mechanic checked for vacuum leak and it was fine. He is suspecting a bad injector, but suggested I start off with a bottle of injector cleaner and high octane fuel. Well, that seemed to work and the light went out, until it came back on... it didn’t come back on until the tank was empty, though, and that’s also when it came on the first time.
So, is it coincidence that the sensors report an issue when tank is empty, or is there water or something floating on top of the fuel?
I’m gonna do another bottle of cleaner and high octane, and if the light goes off will have my wife keep tank at no less than 1/4.
Anyway, I guess I’m just seeking an opinion about my theory. Having this properly diagnosed will be expensive, and the truck has been running just fine after the cleaner.
2016 GMC Yukon XL. Not a Denali, so it’s the smaller V8 (5.1L?) 50k miles.
Anyway, check engine came on. OBD reader showed air/fuel ratio error (my cheap reader didn’t say if it was lean or rich) and cold start rough idle. The latter was evident - start truck in the morning and it was rough for a few seconds, then smoothed out and was fine.
My mechanic checked for vacuum leak and it was fine. He is suspecting a bad injector, but suggested I start off with a bottle of injector cleaner and high octane fuel. Well, that seemed to work and the light went out, until it came back on... it didn’t come back on until the tank was empty, though, and that’s also when it came on the first time.
So, is it coincidence that the sensors report an issue when tank is empty, or is there water or something floating on top of the fuel?
I’m gonna do another bottle of cleaner and high octane, and if the light goes off will have my wife keep tank at no less than 1/4.
Anyway, I guess I’m just seeking an opinion about my theory. Having this properly diagnosed will be expensive, and the truck has been running just fine after the cleaner.
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