misfire

[Carl48]

08 base PT, 18k miles...started it up this morning to go to church and noticed it was running rough , like it was missing...let it idle a few moments and put it into reverse at which point the "check engine" light came on...oh well, put it in drive and pulled back into the driveway and all of a sudden the roughness goes away and the light goes off. Drove it with no further problems this morning. Just got out the code reader and have a P0304 (#4 cylinder misfire). Any ideas why?...have only had this PT a couple months...not an expert on their idosyncrasies (yet). btw...tried the key on,off trick a number of times trying to retrieve codes but get no display on the odometer...works fine every time on my Jeep, what is the secret on the PT? Thanks.

[CREWZIN]

No secret on the PT. You do have to turn the key 3 times within 5 seconds. Maybe you weren't tuning fast enough.

The misfire on #4 sounds like it was only temporary and I wouldn't worry about it unless it comes back. You should still be under warranty so I don't want to tell you to start switching things (plugs/wires) around to find out the cause of your misfire.

[Carl48]

Crewzin...thanks for the quick reply. Went out and tried cycling the key faster and it works if it is cycled quickly...thats a fast 5 seconds. Interestingly enough when extracting the code with the key on-off method, the odometer shows no numeric code, just "done". With my plug-in reader, the P0304 misfire code comes up...tend to believe the reader in this case because the engine was misfiring. In the meantime, going to just keep an eye on things, might investigate the plug wires if it happens again...heard they are a bit of an issue on the PT.

[CREWZIN]

Yes, the stock wires are.....shall we put it nicely CRAP. Replacing them with any decent wires will cure a lot of problems that come up from owners. We recommend die-lectric grease on both ends of each wire to keep moisture out, make a good electrical connection and make it easy the next time the wires have to be changed. Anti-seize on the plug threads also.

Not sure why it didn't show a code (supposed to say "done" when no code is set) when your reader did show something. Clearing most codes is done by disconnecting the negative battery terminal

[Carl48]

Misfired slightly again this morning, but no "check engine" light this time. Any recommendations on spark plugs?...copper vs platinum...had some bad luck with platinums in another vehicle years ago. What is working good for you guys? Thanks. (08, base, auto).

[CREWZIN]

Platinum's are OK in the cruiser as long as it's not a turbo. A lot of us use Champion Double Platinum #7570. I've had mine in for 48K and just about to change them at the big 100K. Starts great, runs well and a smooth idle.

[StoneWhitePT2]

I had this happen to me only a couple times but it was years ago and my pt on had 10-20k miles on it, 36k now. Like you said it smoothed out within a few minutes or when i turned it off and restarted... never took it to the dealer at all and Since then, Ive never had the same problem again.. pretty weird.

[atlctuzr]

Which spark plugs are recommended for use in the Turbo Lites? What should the gap be? The dealer told me there is service bulletin that notes the computer should also be reprogrammed (on the 2005) to help eliminate this issue.

[CREWZIN]

Although one person on this forum uses platinum's in a Turbo, most say to stick with copper plugs as the turbo runs too hot for the platinum. The gap for the GT's is around .032in and I'd think for yours it would be the same. I don't know anything about that particular TSB.

[mopar_man]

Myself and a lot of others over at PTCrew use NGK Iridiums. I got mine from Modern Performance. I'm also running Granatelli wires from them. Sparkplugs.com also has the Iridiums too but the price is less than $1 difference for all 4. You can check your local parts stores as well but I found the online ones to be considerably cheaper.