3800 P0300

[TonzKnock-G]

If I have a P0300(slight misfire ONLY at idle) is it hurting my performance since it is a idle issue? I guess im thinking that since the PCM sees the code maybe it will hold me back somehow. Although I have No misfires during cruising or WOT. Is it hurting my gas mileage? Thanks for any input.

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[MIKES3]

Originally posted by tonzcompg04@Mar 9 2006, 02:23 PM
If I have a P0300(slight misfire ONLY at idle) is it hurting my performance since it is a idle issue?  I guess im thinking that since the PCM sees the code maybe it will hold me back somehow.  Although I have No misfires during cruising or WOT.  Is it hurting my gas mileage? Thanks for any input.

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The question you have to ask yourself is why are you misfiring at idle. You should check you saprk plugs. When was the las time you replaced them? Are they colder? Do you have stock wires?

Mike

 

[TonzKnock-G]

Stock everything (plugs & wires). Way back when I bought the car no miles (now 27K) I had a idle misfire issue (only happened after extended period of being idle) and was in and out of the dealership several times. They changed plugs, wires, injector and still had the same issue. It ended up being a PCM update that came out several months after I bought the car. No problems after that for a while. Then one time a while after the PCM update I did throw the code again but it cleared itself after 2 days.(?) I talked to a tech at gm and he said that the code cleared itself because the car didnt misfire anymore for so many driving cycles so the pcm cleared the code. (ok then) Well after that occasion it didnt happen again.

 

[framos242]

Tony,

Check the MAF, MAF circuit fuse & the MAF wiring as well.

 

[TonzKnock-G]

I ended up buying a DHP off of someone on clubgp. The first thing that came to my mind after buying this DHP was did it have the latest code fixing my misfire issues. After installing DHP and running it for a few days I got the same misfire problem. Note that this PCM was originally Intense then was reflashed by DHP after the Intense issues arrised. I ended up hooking up with Charles ( who helped my out even though I didnt buy off DHP *nice guy*) He checked it out and found that it didnt have the latest data. He did his thing and sent me on my way! A few weeks later after installing the DHP again I threw the same code. So I just took it out and put it in my closet.

 

[TonzKnock-G]

Sorry I couldnt get all this into one post but work is killing me right now! So to make a long story short Ive been debating wether or not to put DHP back in KNOWING that nothing is wrong (mechanically speaking) since I have no issues running stock PCM. Sorry If I confused the hell out of everyone with all these separate posts.

I really dont wanna bother Charles again since he already helped me out. Im just wondering if when I put DHP back in and if it does throw the P0300 code again will it affect performance? (remember that im not getting misfires during WOT according to my scans from back then which I dont have anymore).