Well I spoke with a GM technician (my grandfather worked for GM so he can pull some BIG strings) and he gave me some serious words of advice...I have been normally using 93 octane every time I fill up. This is sometimes bad for engines not suitable for higher burning gasoline. The temperature difference from 93 octane to 89 or 87 can be upwards of 40 degrees and can cause serious problems to the spark plugs or wires on a stock motor. So regardless, I switched to 89, drove 100 miles on the highway and she never went off. If it does go off again, he said it could be 4 things
1) valve train failure
2)vacuum misfire
3)ignition misfire
4)EGR Failure
I only know of an ignition failure and vacuum leak...the others (valve train and EGR), he siad the dealer would most likely replace the engine
well, i was told by the mechanics at the dealer where i go in burbank, that there went a memo out about a year ago or less that said "GM states that all of their engines should run 87 and no higher" it doesnt help and can only cause problems....so i run 87...have you heard different
I started using 87 oct about a month ago. Today I noticed it pinging fairly bad (had radio down for a change). So, I filled up with 93oct to get the ping out. I think 89 is perfect medium for our trucks. Maybe there was another reason it pinged, but I really cringe at that sound. 89 seams to be perfect for it.
honestly i have listend for pinging and i dont think mine has never done it and i run even 86 in it in arizona...but then again, i may not know it if it was pinging
quickbiker wrote:I started using 87 oct about a month ago. Today I noticed it pinging fairly bad (had radio down for a change). So, I filled up with 93oct to get the ping out. I think 89 is perfect medium for our trucks. Maybe there was another reason it pinged, but I really cringe at that sound. 89 seams to be perfect for it.
I ran 93 for my second & third tankfulls because I thought it was pinging. It didn't help. after taking it in to the dealer for the pinging I found out about the ballance shaft noise most 4.3s have. Most audible with windows up & nothing else on.
Hey Hobie have fun with that wording
Best Regards, Jim
2004 Tahoe, Summit white, loaded up. 06 front air dam, wood interior trim, Shaved Roof Rack, Escalade rear vents, LED Tails, SLP dual cat back exhaust w/ Flowmaster 70 muffler, 20 inch 07 Sierra wheels.
