2002 Seville Misfire on #4

[BSanden11]

Hi, my 2002 Seville started to have a slight miss at idle so i checked the codes and it says misfire on #4. So i changed all the plugs and it seemed to not be as bad for a day or so. Then the light came back on and it said misfire #4 again. So i changed the coil-to-plug boot on #4 and no change. I sprayed ether all around the engine to see if there was a vaccum leak and i couldn't find one. I didn't think it would be the coil since it runs good at higher rpms. So, now im stumped. I was wondering if a fuel injector could be the problem??? The miss is only at around 650 to 900 rpm. Once the engine revs up to 1000 and beyond it runs nice and smooth while sitting and while driving. Any ideas?

- Beau

[maxwedge]

Welcome to AF, this can be caused by a weak injector, a vacuum leak, or low compression in that cylinder. A full scan can do a power balance test and a injector test.

[danielsatur]

Take a bad injector to a diesel shop for a good micro bath, blow out, and flow rate test.

[BSanden11]

Hey guys, thanks for the tips. Unfortunatly, i tried all of em and nothing worked. So I broke down and took it to the dealership for a check up. It turns out it was the one thing i didn't think it ever would be - the coil. So i slapped on a new coil pack on the front bank and it runs like a caddy again.