Need help with SES light code PO300
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From: sojourning....looking for my city whose builder and maker is God.
Need help with SES light code PO300 Took it to the dealer, they said it was misfire at idle below 950 RPMs. They kept if for a day tried a lot of different things. They thought it might have been the computer itself so they replaced it.
They know about my mods like the 3300 stall converter I have and they are cool about it. I had that converter installled as soon as I bought the car last Feb. The only problems I have had with that is, at idle sometimes the car would try to die on me, but just every now and then not offten, and around town at lower speeds I would have to have the car in 3rd. gear because the car would not down shift right.
From reading post on here I came to believe the downshifting problem was caused by false misfire. The SES light never came on.
One of the last mods I did was the cutout (mods in sig). Not long after the cutout, the downshifting problem got better and better, untill I could drive it in overdrive again without any trouble. Don’t know if it has anything to do with the cutout or not.
My husband and I have never reset our computers after all the mods we have done. The guys at the dealership told him to disconnect the neg. Battery cable then the pos. Cable. Let it sit 10 min. Then hooked it back up the neg. Cable first, then pos. Start car let run for a min or 2 then turned on the a/c. Then turn car back off, waited about 10 min. Then drove car around for a while.
Worse thing I have done to my car, it hasn’t been the same again. I could hardly keep the car going at idle. When I was slowing down to make a turn the car would die on me. Did that for a couple of days, then the SES light came on. That’s when I took it to the dealer and they replaced the computer. Didn’t get 2 miles down the road and the light came back on again. And it still dies on me if I don’t keep the rpms above 1000 or so.
I tried to reset it again by removing the 2 fuses in the engine comparrtment with the key on, let sit a few min. Turned key off, replaced fuses. After a few miles down the road the light came back on. Did this 2 times.
I believe it has something to do with the torque convert and need to tune the pcm. I ordered LS1 Edit, please help me on what to do with it.
Sorry this post is so long.
Thank-you, Becky
They know about my mods like the 3300 stall converter I have and they are cool about it. I had that converter installled as soon as I bought the car last Feb. The only problems I have had with that is, at idle sometimes the car would try to die on me, but just every now and then not offten, and around town at lower speeds I would have to have the car in 3rd. gear because the car would not down shift right.
From reading post on here I came to believe the downshifting problem was caused by false misfire. The SES light never came on.
One of the last mods I did was the cutout (mods in sig). Not long after the cutout, the downshifting problem got better and better, untill I could drive it in overdrive again without any trouble. Don’t know if it has anything to do with the cutout or not.
My husband and I have never reset our computers after all the mods we have done. The guys at the dealership told him to disconnect the neg. Battery cable then the pos. Cable. Let it sit 10 min. Then hooked it back up the neg. Cable first, then pos. Start car let run for a min or 2 then turned on the a/c. Then turn car back off, waited about 10 min. Then drove car around for a while.
Worse thing I have done to my car, it hasn’t been the same again. I could hardly keep the car going at idle. When I was slowing down to make a turn the car would die on me. Did that for a couple of days, then the SES light came on. That’s when I took it to the dealer and they replaced the computer. Didn’t get 2 miles down the road and the light came back on again. And it still dies on me if I don’t keep the rpms above 1000 or so.
I tried to reset it again by removing the 2 fuses in the engine comparrtment with the key on, let sit a few min. Turned key off, replaced fuses. After a few miles down the road the light came back on. Did this 2 times.
I believe it has something to do with the torque convert and need to tune the pcm. I ordered LS1 Edit, please help me on what to do with it.
Sorry this post is so long.
Thank-you, Becky
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From: corpus christi
Re: Need help with SES light code PO300 dude,i mean chick,i was having the same problem after installing my nitrous kit.i also got a 300 code(random misfire)but i just hooked up a codescanner and it cleared the code.i also have ls1 edit,but you really dont wanna take that outta the system,its a safety net(sort of).i got a coverter but it runs fine.have you checked the sparkplugs,wires,and other ignition components?or even your mass air?
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From: On the Bumper!
Re: Need help with SES light code PO300 Your problem with PO300 is caused by the ported MAF. I still get it on ocassion , but it doesn't throw the SES light. You may want to try to raise the idle with the adjustment screw to maintain a more stable idle. Your pcm is probably getting erratic air flow through the MAF now. LS1edit will be able to eliminate the problem though. It doesn't hurt performance either. It is just annoying. These little issues are the price we pay for fast toys. It is a very common code and LS1 issue. Join the club. Good luck!
James
James
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From: sojourning....looking for my city whose builder and maker is God.
Re: Need help with SES light code PO300 </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong>It sounds like your car is cammin hard, even though you don't have one <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
Alot of us cammed folks go through what you are talking about. Do you have autotap? If so, what is your IAC count? If you turn the air conditioner on, will the car run normal, or does it die?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I don't have autotap yet, so I don't know what my IAC count is. The car runs rougher when the A/C is on.
<strong>It sounds like your car is cammin hard, even though you don't have one <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
Alot of us cammed folks go through what you are talking about. Do you have autotap? If so, what is your IAC count? If you turn the air conditioner on, will the car run normal, or does it die?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I don't have autotap yet, so I don't know what my IAC count is. The car runs rougher when the A/C is on.
Re: Need help with SES light code PO300 It sounds like your car is cammin hard, even though you don't have one <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
Alot of us cammed folks go through what you are talking about. Do you have autotap? If so, what is your IAC count? If you turn the air conditioner on, will the car run normal, or does it die?
<small>[ August 11, 2002, 01:01 PM: Message edited by: NoGo ]</small>
Alot of us cammed folks go through what you are talking about. Do you have autotap? If so, what is your IAC count? If you turn the air conditioner on, will the car run normal, or does it die?
<small>[ August 11, 2002, 01:01 PM: Message edited by: NoGo ]</small>
