Check engine light flashing

[Deerassassin]

I have a 03 Sierra 1500 z71 4x4 5.3. Yesterday my check engine light started blinking and the stopped when I was at a stop light but light was still on then started blinking again when I started driving. I have lost a lot of power. I read that it might be the cats it has stock cats. It has 220,000 miles. It hasn't given me any messages and it sounds different under acceleration. Please help

 

[happy 2011]

well if the check engine light is FLASHING then that means you have a missfire that will cause damage to your cats if you do not adress it.

So get your skip fixed before you have to buy cats. Cheaper to just fix it now.

 

[Deerassassin]

What causes it to misfire?

 

[happy 2011]

there are a lot of reason it will or can misfire. If your not familiar with ignition systems or basic motors than take it to a repair shop (not a chain or dealer) and have them diag it and give you a price. It will be cheeper and easyer than trying to just replace parts.

 

[Deerassassin]

Thanks It's going to the shop monday. Going to fix the misfire deal and get a new rear main seal.