duran492

im pretty sure that im gettin bad gas mileage, a cylinder or 2 is bad on my 03 tis. I'm positive its the coil pack.

does anyone know if its a minor difference or major wheter it's 1 or 2 bad coil packs.

ANC297

iTrader: (2)

The car will most likely not run with 2 packs bad.

jra8858

Do you have a cel? If so what codes are you getting?

Karanx7

iTrader: (2)

Car might not even trip a CEL with 1 bad coilpack. With 2 bad coils, your engine will run terribly.

3.2TLc

Yeah, as said "check the codes". There are other things that can also cause poor gas mileage and runability issues.
How many miles ? When was the last tune-up ? Have you cleaned the EGR passageways ?

Try some fuel system cleaner, check all the wiring and vac connections, maybe something simple that just needs tightened or replaced ?

Check the injectors, plugs, coils and compression if you're sure it's a lazy cylinder.

ANC297

iTrader: (2)

1 bad coil will throw a cel, it did for me back in sept

duran492

it threw a couple codes at me .. it told me i had 2 bad coil packs .. i did some research on here and someone said one bad pack can send 2 codes ..

i checked the front 3 and they are fine .. i could one get to the one far left in the back and that one is fine ..

some times when i start it "glug-glugs", then once i take off it goes away and a normal idle comes back. i have not tried and fuel cleaners at all .. but i will today! ..

webmastir

You sure it's not EGR/IACV related?

Karanx7

iTrader: (2)

Strange, mine was running with a bad coil for like a week with no CEL. Guess it just depends on the knock sensor's readings.

ANC297

iTrader: (2)

Probably uses the crank sensor as a misfire monitor like many other vehicles do, when the coil misses completely it sees a drop in crank rotational speed which it determines is a misfire. Your coil may have been producing a weak spark which the pcm did not interpret as a misfire

OP, what codes did it produce? p030x codes?
And how did you test your coils packs?