Mack_Sant

Ok... So I have been researching for the past week and half now on misfire issues and solutions. none of the stories or problems sound like mine. One came close but it was misfire on cold and hot start. My 8 only misfires on COLD START. It will misfire for about 20-30 seconds, exhaust sounds different of course because its misfiring and vibrations from it as well. It'll then decide its a car and goes to its normal warm up cycle at about 2500 RPM and nothing from then. Ill clear the code and it wont pop up till the next start. It varies between P0300 and P0302 when I clear the codes.

I have been messing with all my ignition equipment trying to figure out whats wrong. Plugs were done back on new years day. ignition coils and wires to my knowledge have never been done. I bought the car back in August of last year with 72xxx miles on it. It now has 82xxx. I have tested the resistances like it shows in the service manual on the coils and wires. Since P0302 is my rear rotor I swapped the coils to see if the problem then popped up in the front rotor. No difference same P0302. Back when I bought the car I got it compression checked, and was not perfect but wasn't bad, more like a little above average.

A little more info is that some days it has misfired on every cold start and others it hasnt misfired at all. Also, I work at an emissions testing station and we used the exhaust "sniffer" probe to see if I had an hydrocarbons in my coolant. It read 57 PPM. Does anyone know the allowed amount of HC in coolant? Possible coolant seal, coolant in housing spins and burns up causing misfire? I have seen some clouds out my exhaust the past few days. But its been colder weather and quite a bit of rain...

Some people might say look and search more... seen it a thousand times reading around here. flame me or whatever but atleast link me to this information. I have not read anything on a misfire on cold start only changing to the car running fine. please help.

niteshade247

Start with the coils I see you say that you don't think they have ever been changed. Check you shaft sensor to could be dirty.

Mack_Sant

So update on the past two days. Yesterday it didnt misfire once. may have said that in the above post. and I havent cleared the code myself in the past couple days and today it didnt misfire either and the CEL turned off. it went through its drive cycles.