OTHREETLS

I had a misfire on 3 of my coils. I changed the ones that were misfiring and haven't had any check engine codes return.

But since I changed the 3 coils, my mileage has been worst. Same type of driving, same premium gas from same gas station. Normal tank I get around 260 miles. Now, I'm getting 219 with the gas light on!

Any chance this is related to the coils?

thoiboi

What type of coils did you use?

horseshoez

iTrader: (2)

How long did you drive the car with the bad coils? I ask because you may have damaged the catalytic converter if you drove too many miles.

OTHREETLS

I got them from Amazon after reading a lot of people did the same thing instead of paying $70 each. I also changed them like a week after the check engine light came on

Skirmich

You had 3 miss fires at the same time? Did the car run badly as in The coil was not firing?
OR you just went and replaced the 3 coils without diagnose?

thoiboi

Brand?

OTHREETLS

I believe they are intermotor

OTHREETLS

The car seemed to run fine, but the check engine came on for the second time and gave misfire codes. The shop recommended I change coils

thoiboi

well that's why


stick with OEM or OEM equivalent coils/plugs or face consequences like worse gas mileage. The savings in the parts don't outweigh the increase in gas consumption

OTHREETLS

Ah damn. I was trying to avoid paying $70 x6!

thoiboi

Now you get to just pay for extra gas instead!


You don't need to replace all 6.. just the ones that are bad.

horseshoez

iTrader: (2)

Agreed, that said, I'm thinking only one was bad all along.

Skirmich

There is a really, REALLY low chance more than 1 coil was bad so you could have gone with a good brand Coil Plug instead...
I will advise you not to pull the trigger on what some shop tells you right away and get second opinions next time. Bad coil plugs are a common issue here in the forums so we already know how to properly diagnose them and its very easy (no need for mechanic).

grandlaker

If car idles rough it’s essy to troubleshoot coil issues. Just disconnect the harness on each coil one at a time. Car should idle even worse with each coil you disconnect. When one doesn’t change, that’s a good indication you found the bad coil or spark plug. Then swap coil with an existing to verify, or spark plug to nail which is bad.