1-3-2-4 Posted March 30, 2009 Share Posted March 30, 2009 I have noticed this and so did the shop where I had my exhaust work done at.. it only happens when the car has been sitting for say 3+ hours when you start it up it runs rough as if it has a misfire but no CEL and if you give it a little throttle it shows up as rocking the whole engine and sounding more like a misfire.. but I can't pinpoint where it's coming from and why it happens... the funny thing is say you start the car up again after it's warmed up and all it wont happen anymore until the car has sat for another 3+ hours.. I did get a sound clip of it but so far no one has responded back to my post.. I might have to try the USMB and at the very last the stealership. I can upload the file if you want to hear what I mean. Link to comment Share on other sites More sharing options...
987687 Posted March 30, 2009 Share Posted March 30, 2009 Yes, it is possible. I actually had a sparkplug come out of my engine (WTF?). But I didn't get a CEL from that. (I would expect that to cause a misfire....) Anyway, I had a bad plug wire causing occasional mis fire. but no CEL. What I did was go up some steep hills at WOT which finally upset the ECU enough to throw a CEL for misfire. then I knew which cylinder it was. Link to comment Share on other sites More sharing options...
KnifeyMcShanker Posted March 31, 2009 Share Posted March 31, 2009 I think misfire codes are just thrown when a certain per cent of your fires over a period of time are misfires, not when there is just one. Link to comment Share on other sites More sharing options...
987687 Posted March 31, 2009 Share Posted March 31, 2009 I think misfire codes are just thrown when a certain per cent of your fires over a period of time are misfires, not when there is just one. Exactly, and that's why going WOT up hills makes the CEL come on. If you have a misfire issue, putting the engine under a lot of stress will make it worse, throwing a CEL. Link to comment Share on other sites More sharing options...
1-3-2-4 Posted April 1, 2009 Author Share Posted April 1, 2009 that wont work since it only happens when the motor is cold and the rough running is gone before 30 seconds.. thats why it's hard to pin-point... and if you turn the car off and start it up again it wont return until the car has been sitting for 3+ hours. Link to comment Share on other sites More sharing options...
987687 Posted April 1, 2009 Share Posted April 1, 2009 Huh. if it only happens in the first 30 secs and doesn't happen any other time. I'd ignore it. Link to comment Share on other sites More sharing options...
1-3-2-4 Posted April 1, 2009 Author Share Posted April 1, 2009 It's one of those issues where you need to see the car in person... if I need to I will just bite the bullet and take the car to the dealer. Link to comment Share on other sites More sharing options...
levis76 Posted April 1, 2009 Share Posted April 1, 2009 How old are the plugs/wires? Are the plugs snug? Any mods done on the engine? My 98 LGT was constantly misfiring after I did the Neon coil mod and it didnt throw a CEL until I opened it up getting on the freeway one day. I tried a tank of midgrade (89octane) hoping it would be that simple and it was. I havent had a problem for several weeks now, unless you call spending an extra nickel per gallon a problem. Truth be told, the NA subies have such a high compression ratio that you should run at least midgrade. Anyways, you could try it, and its probably going to be the easiest suggestion your going to get, except for the 'just ignore it' comment. Link to comment Share on other sites More sharing options...
987687 Posted April 1, 2009 Share Posted April 1, 2009 I put mid grade in my car the other day because the gas station was out of regular. My friend told me it was bad for my car, and the engine would explode if I used the wrong grade. When I asked why, he said "the higher octain will just make it blow up" He was serious too :lol: Link to comment Share on other sites More sharing options...
levis76 Posted April 1, 2009 Share Posted April 1, 2009 Link to comment Share on other sites More sharing options...
old legacy GT Posted April 1, 2009 Share Posted April 1, 2009 higher octane blow up an engine that is the funnyiest car talk I've heard in a while!!!!! the higher the octane the less chance you have of blowing i up resistance to explode helllo!!! Link to comment Share on other sites More sharing options...
987687 Posted April 1, 2009 Share Posted April 1, 2009 higher octane blow up an engine that is the funnyiest car talk I've heard in a while!!!!! the higher the octane the less chance you have of blowing i up resistance to explode helllo!!! He thought that octian = wicked explosive, and the more you have, the more explosive the gas is. Nothing I said changed his mind .... *sigh* Link to comment Share on other sites More sharing options...
dplacen Posted April 1, 2009 Share Posted April 1, 2009 I use midgrade gas on my car all the time never had a prolem. I put Exxon plus, that is the only gas i use. Link to comment Share on other sites More sharing options...
KnifeyMcShanker Posted April 1, 2009 Share Posted April 1, 2009 Yeah, higher octane gas actually has less BTU (energy potential) than lower octane... Link to comment Share on other sites More sharing options...
987687 Posted April 1, 2009 Share Posted April 1, 2009 I know, I know.... maybe I'll direct him to this thread... Link to comment Share on other sites More sharing options...
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