OK guys I am at my witts end over this. I have noticed this twice now in the last 2 days. I had my 03 Tahoe running up the Highway about 85mph. and I noticed the CEL started blinking. Not sure of exactly how many times, But at least 5-6 times. Then it stopped. No gauges reading out of normal. Same thing happened again today. on highway ,running about 80mph or so and it started blinking. But the light is off now. I plugged in a OBD reader and there isn't any codes. So anyone have any ideas? thanks everyone
CEL Mystery
- Thread starter Mike1980B
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
so basically im looking at replacing all 8 coils. because there is no way for me to know which one/ones are misfiring. I have already put new wires and plugs in it 2 months ago. As far as I know the coils could be original, with 186K miles on them. Local Autozone has replacement coils at 40 bucks a piece. That hurts my feelings :-(
You could get it properly diagnosed if you don't want to throw parts at it. Any GM dealer can look at which cylinder is misfiring on the GM scan tool. If you're one who doesn't like the dealer for whatever reason, an indy with a good aftermarket scan tool should be able to see that information as well.
M3PO
Full Access Member
Agreed, so many think throwing parts at a repair is the cheaper way to go, but unfortunately many end buying more parts than needed and/or paying a shop for repairs/diagnoses.
afpj
Full Access Member
- Joined
- Sep 16, 2009
- Posts
- 803
- Reaction score
- 355
If you replaced plugs & wires 2 months ago, check to make sure the plugs and wires are still seated well. I had one plug back out a little after 500 miles, only noticed it because it was vibrating when I was inspecting everything with the engine running. It was less than an 8th of a turn, but still, stuff happens. Hopefully it's that simple for ya.
i dont think it could be that type of issue. Mainly because the issue only seems to be happening at highway speeds of about 80mph. Never happens at a slower speed. I used to run into similar issues when i was working at the marina. boat would run great up to 3/4 throttle. break up and misfire at WOT. swap in a new coil and problem went away. I mean i suppose all of my coils could use a replacing. they all look to be original, with surface rust on them. so they would be 9 years old with 186,000+ miles on them. But yes I would like to know which one is the actual problem.
Vinniety
Full Access Member
if you have time on your hand you can buy a new or a good tested used coil and swap it out with one and see if it happens again. If so swap it out with the next and keep going. I know it sounds like a pain but if you want to save money there you go. I see you have the upgraded taylor wires, new plugs and also 186k miles so maybe a nice new set of coils wouldn't be a bad idea. I guess you can also compare the cost for the dealer to diagnose with the steps i said above. I do have a spare coil because i thought that was my issue when i had the check engine light on but it wasn't. I had a intake gasket throwing misfire codes.
well i was poking around under the hood earlier today, inspecting things and checking fluids. I did find 3 plug wires that weren't clicked 100% into the coil. maybe just that tiny bit could be causing the misfire. I have a lot of highway running to do over the weekend, so we'll see if it fixed the problem. thanks for the input guys
