check engine light mad codes

lazymun

New Member
Mar 5, 2006
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ok this is an on going project that I'm getting poor doing. my car was runnign like crap after I changed my oil 2 weeks ago like I posted. I was helped out my members on the site who in formed me to clean the MAF and change fuel filter. (hesitation, stalling, no power reseting computer) well today was the last draw so I bought an OBD 2 scanner and I found a few codes this afternoon: P0301, P0304, P0308 (misfire in cyl 1,4,8) P1131, & P1151 (insuff. switching 02 bank 1 sensor 1 sensor lean & H02S bank 2 sensor 1 insuff. switching lean mean) so I again clean the MAF using CRC eletric parts cleanner and changed the coils in cyl. 4 & 8 I didn't nothing else cause the other 3 codes were still pending. no I drove the car and it still had a misfireing sound to it but threw no codes except P0304 so I pulled the plug it was foulled all black looking I cleaned it up for the time being so I could get to the parts store to buy plug (I got G- force NGK cause they had no motorsports plug are they any good????) as of right now I didn't put the plugs in yet and I am still throwing code P0304 (misfire cyl 4) and now I'm also getting P0174 (System too lean bank 2)

Is the MAF shot to hell and in need of replace ment please help
 
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ok you might have a bad maf but start out with this.

remove all the plugs and clean them really well, even better if you can find a place with a spark plug cleaner you can use ( it's a little sandblaster you put plugs in and it cleans them)

then change the oil again. with that many misfire the oil has fuel contamination then see if it runs better.

try that and post back.
 
ok I changed the plugs and they were all black not good haha. I cleaned the MAF once again hope to maybe find a miricle before purchaseing a new one for $188. I also reset the the computer to reset the fuel trim and shes running a lot better I have all my power back in the high end but shes still slacking in the low end when I go to accerrate the motor fludders until I get to about 2500 RPM where the power picks up again and my OBD 2 scanner isn't picking up any codes. any last Ideas?????
 
lazymun said:
ok I changed the plugs and they were all black not good haha. I cleaned the MAF once again hope to maybe find a miricle before purchaseing a new one for $188. I also reset the the computer to reset the fuel trim and shes running a lot better I have all my power back in the high end but shes still slacking in the low end when I go to accerrate the motor fludders until I get to about 2500 RPM where the power picks up again and my OBD 2 scanner isn't picking up any codes. any last Ideas?????


I bet your oil is fuel washed. I have posted this a bunch of times, when the oil becomes fuel washed it causes the plugs to foul out and misfires becuase the fuel in the oil washes the rings down so you don't get full compression and the fuel vapors themselfs in the oil richen the fuel mixture.

it's not running any better above 2500 it just feels like it does becuase the engine is spinning faster so you don't feel the misfires and studdering.

you may still need a maf but I would change the oil and filter and clean all the plugs again and go from there.
 
grrr haha so much for getting better now on my way home from work the check engine light comes on again and the car start hestitating again. I have codes for misfire in cyl. 4 and 8 again.

so heres what I'll do I'll change the oil and clean the new plugs and buy a MAF and I hope it fixs the problem

anyone no where I can pay less for a MAF
Advanced auto is like $188
 
mity2 said:
and how did he get that after just changing oil???


well that makes no sense.

oil will get contaminated from really bad misfires. that is seperate from the start of this problem.

I could not tell you why it would run fine, and then misfire on new oil. somthing else happend when that oil was changed. did he clean the maf at the same time?
 
If your setting lean codes, but your plugs are fuel fouled you probably have a bad o2 sensor on that bank, or both frt o2 sensors are hooped. Try disconnecting both frt o2 sensors. clean the fouled plugs. reset the computer and drive it. It will set codes but if your o2 sensors are bad it should run fine.
 
ok as of right now I put a new maf on the car and changed the oil and filter, replaced the fouled plugs in 4 & 8, the car still runns like **** and as only half the power so I will now disconect the 2 front 02 sensors cause I'm throwing a code for bank 1 & 2 and I have pending misfires on 4 & 8 again and a pending code for mutiple misfires. so I hope ing that disconnecting the 02 sensors and reseting the computer will make the car runn good to clarify the last thing I need are those peske sensors and the rest of the pending codes will disappear.........
 
lazymun. don't replace the 02 sensors. that will not cause a misfire. the 02 sensors are a secondary sensor to provide feedback to the pcm. the 02's are used to double check the mixture and can not influence the tune to the point of causing misfires.

you have lean readings on both banks because you have misfires on both banks, when you have a misfire you will get a lean reading due to the extra unburned oxygen in the exhaust. the sensor can not pick up the unburned fuel so it reads lean.

so lets start from the beginning.

we need to know when did this start happening. what exact steps were done to remedy this problem and in what order. have you checked your coils.

It's realy hard to diag this over the internet because you do not have access to all the tools I have in my shop. Plus I am not there to see the problem.

you need to check these things.

1. plugs
2. coil packs

then if it's not that I assume your are right about the plugs being fuel soaked that leaves only the wiring and the pcm as possible problem areas.
 
from the start I was picking up maf misfuction codes, and misfires in 4 & 8 so I changed all plugs and replaced 4&8 coils. computer reset

then again changed 4 coil due to code not disappearing. computer reset
then replaced, 4 & 8 plugs again, oil and filter change, MAF replacement, computer reset

now I have front 02s disconected and I'm throwing 4 codes: 02 bank lean, misfire in 4 (which I just can't get rid of, and 2 heater circuit sensor codes)

as we speak I'm reseting the computer and reseting fuel trim

you said tools that you have that I don't tell me I might just have it. is there a special way to check and see if the new coil is working?
 
lazymun said:
from the start I was picking up maf misfuction codes, and misfires in 4 & 8 so I changed all plugs and replaced 4&8 coils. computer reset

then again changed 4 coil due to code not disappearing. computer reset
then replaced, 4 & 8 plugs again, oil and filter change, MAF replacement, computer reset

now I have front 02s disconected and I'm throwing 4 codes: 02 bank lean, misfire in 4 (which I just can't get rid of, and 2 heater circuit sensor codes)

as we speak I'm reseting the computer and reseting fuel trim

you said tools that you have that I don't tell me I might just have it. is there a special way to check and see if the new coil is working?

At the dealer we have scan tools that can aid in pinpoint testing, the wds offers injector flow tests, power balance, relitive compression and ignition tests. All of those would help big time on this problem


I think we are at the point with this when you need to swap the #4 injector with another cylinder and see if the misfire moves. if that don't work then you need to check compression. if compression is good then your problem is in the harness or the PCM

and please plug the 02's back in. that is not going to help. It's not the 02 sensors causing this problem.
 
ok I got a tip from a freind that there might for some weird outrageous reason may be water in my fuel so I drain the tank what do you know not a lot of fuel in a 1/4 tank but a lot of water so I changed the fuel filter and took it to get a motor vac or whatever to get all the water and fuel out of the lines and injector when I get it back I'll go from there
 
lazymun said:
ok I got a tip from a freind that there might for some weird outrageous reason may be water in my fuel so I drain the tank what do you know not a lot of fuel in a 1/4 tank but a lot of water so I changed the fuel filter and took it to get a motor vac or whatever to get all the water and fuel out of the lines and injector when I get it back I'll go from there


sounds like somebody needs to have their teeth removed from their mouth with a fist.
 
ok so sadly the truth be known there was water in the fuel tank and as well some oilliy substance and something that looked like soggy cracks I dunno I sent the tank out to get flushed and cleaned out. I got it back today and the misfires are gone but when I floor the gas pedal the motor craps out so tomarrow I'm gonna toy around a little bit and get her back to par. so I can start adding headers and slp exhaust