CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Misfire, Oil in Air intake, No start

was driving my Saturn when it felt like a cylinder start to misfire. Service Stabilitrak came up and traction control turned off causing engine light to blink. Code came back cylinder 4 misfire. Knowing I was due for new plugs and air filter I purchased parts. Go to move inside to work on it and it will not turn over. it had started four hours before. So I dive in…

Found a fair amount of oil/water in air intake hose between filter and intake. Intake had oily coat and could tell heat was burning oil on intake walls. Pretty sure this is not normal? Noticed a hole had been burnt/rubbed into hose connecting PCV to intake/filter hose. Guessing loss of vacuum could be the cause for oil in intake? PCV bad maybe? Moving on to plugs.

I have only changed the 3 plugs at the front of the engine since I ran out of daylight. Plugs appeared to have a little bit of oil (maybe?) on/around electrode. Ignition coils of the three looked pretty decent. Going to attempt to get to the other 3 plugs tomorrow. They made them extremely difficult to get to.

It is a 2008 with 160Kish miles so I’m assuming I’m stumbling upon multiple issues at once. Only other known issue the Outlook has that I don’t think is related but I wouldn’t really know is the evap purge canister on the fuel tank needs replaced.

Any suggestions or insight on what kind of trouble I may be in?

Do the maintenance, fix the hose to the PCV, check the air filter condition, reset the check engine light, start it, drive it, and report back.

Got plugs and air filter changed. PCV valve appears to just be a thru tube and wasn’t clogged. Not sure if I’m missing something there?

Still wouldn’t start. (Had battery charger hooked up to keep my battery voltage up.) Found, pulled, cleaned, and out back the crank sensor thinking that could’ve gone bad. Two attempts and the vehicle start. Still misfiring on cylinder. Idling between 600/800rpm with a flutter from the misfire. Thing to do next I believe is replace ignition coil on misfiring cylinder.

All spark plugs seem to have oil residue around electrode. I don’t think that’s suppose to happen. Unless I’m mistaking it for fuel?

Update: it was the ignition coil on the misfiring cylinder. Running smooth as ever now. Will check on oil in intake after some mileage to see if hose repair resolved that issue.