The root of a check engine light

[viper99d9]

I'm sure everyone and their mom has had a check engine light come on, I was wondering if anyone has been down the specific road I'm on.

The light came on about 3 weeks ago, I took it into my mechanic and he said it was some coolant temp issue or something that wouldn't really be a problem.

I may have felt some shudders in the engine in the time that passed, but 3 weeks and about 800 miles later the light started blinking and the engine was shaking a lot, especially when idling.

I thought it was a transmission issue and took it back to the shop. They found that all 3 ignition coils were shot and replaced them for about $500.

On the way home from the shop, the light came back on. I will have the codes checked again tomorrow.

Has anyone else had a problem like this? I'm thinking that the coils were not the original problem, just a symptom.

[toyomoho]

The CEL does not come on unless there is a problem. It might something as simple as a leaking gas cap gasket but it is best to check out the cause.

The codes are very specific as to the problem.

Autozone or other autoparts stores may read the codes for free or loan out a reader. Check the codes yourself to double check the mechanic.