engine miss, p0300, crank sensor relearn?
01-05-2017, 07:26 AM
#1
Intermediate
Thread Starter
engine miss, p0300, crank sensor relearn?
Ok, so my 03 zo6 has a miss p0300. The car is stock other than a cold air intake. I have pulled the valve cover and looked for broken springs and to make sure that the valves move up and down. I have checked the coil packs and have even swapped them around. The plugs and wires are new with the correct gap and the wires ohm out correct as well. I had the injectors professionally cleaned. I have also replaced all four o2 sensors. The water pump is also new. I have checked for any vacuum leaks and have changed the pcv. There is a new battery and I have cleaned all the grounds I can get my hands on. With all my research I am wondering if the crank sensor may need a relearn or CASE relearn done. Any input would be helpful should I do a CASE relearn? I am not showing a crank sensor code, is there any thing else I should look at.
01-06-2017, 11:51 PM
#2
Ok, so my 03 zo6 has a miss p0300. The car is stock other than a cold air intake. I have pulled the valve cover and looked for broken springs and to make sure that the valves move up and down. I have checked the coil packs and have even swapped them around. The plugs and wires are new with the correct gap and the wires ohm out correct as well. I had the injectors professionally cleaned. I have also replaced all four o2 sensors. The water pump is also new. I have checked for any vacuum leaks and have changed the pcv. There is a new battery and I have cleaned all the grounds I can get my hands on. With all my research I am wondering if the crank sensor may need a relearn or CASE relearn done. Any input would be helpful should I do a CASE relearn? I am not showing a crank sensor code, is there any thing else I should look at.
All these new parts you mention - did you do those before the problems started? Or where you trying stuff to solve a problem?
I put headers on my 2001 6speed back in November. was waiting for a chance to re-connect the O2 sensors, but the car ran great. Just had the check engine light. Got the sensors connected and car has been running lousy. It runs okay on initial start, but in about 2 minutes it starts running lousy. Then it has a miss for about 15 to 20 minutes. After which it runs normally.
You might try to disconnect the O2 sensors and see if it gets better. .... or worse.
02-05-2017, 07:31 PM
#4
Drifting
Possible bad O2 sensors? Have they ever been replaced? You should only need to gchange the two closes to the engine not the one way down stream. The down stream are for only checking to see if the cats are working
02-06-2017, 02:28 PM
#5
- rule out the O2 sensors; until you do that you could be looking in the wrong place. Bad O2 sensors will give a lot of strange codes, and strange issues. 
02-09-2017, 08:59 PM
#6
Le Mans Master
Member Since: Aug 2005
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St. Jude Donor '13-'14-'15
There are 2 kinds of misfires REAL and FALSE---If you do not feel or here a misfire then most likely the P0300 misfire code is FALSE-----
Several aftermarket mods will create false misfires----LT headers being one of them because of the thinner tubes---Also with a manual trans sometimes an aftermarket clutch or flywheel will also create false misfires----
You 1st need to determine if the misfire is real or not---then proceed
Several aftermarket mods will create false misfires----LT headers being one of them because of the thinner tubes---Also with a manual trans sometimes an aftermarket clutch or flywheel will also create false misfires----
You 1st need to determine if the misfire is real or not---then proceed