Jayday

Hows it going

Was driving home the other day and the service engine light started to blink and car started to run like ****. Got home opened the hood an seen the maf sensor cam unplugged so i plugged it back in started the car back up and same problem persisted. so i hooked my code reader up and pulled a p0300 multiple misfire. so i unplugged and battery for awhile and made sure the ecu didn't store some power reconnected the battery to c if u would reset the code which it did and still the car ran like **** and the code came back.... So my question is has anyone else experienced this and what can i do to fix it or what can be the cause of the problem
thanks



2001 z28 with z06 cam ls6 heads and intake full slp loudmouth exhaust and headers.

GMtechmatt

Po300 is general Misfire due to Pcm can not determine where misfire is coming from so it sets a general code,Maf unplugged would creat this due to unmeteed air entering the engine.Plug it back in and Clear the DTC and re check the condition.

How many miles on vehicle? plugs and wires ever changed? are you able to check you long and short term fuel trims?

JaYZeig

iTrader: (11)

plus since its loaded up with fuel, it more than likley needs to clear itself up..let it run a lil and see if it does so! if not your plugs could be on their way out since they were soaked in fuel. platinum plugs dont like that.

1ltcap

p0300 is random/multiple misfire. check your plugs/wires first. simple stuff first.

Jayday

sorry for the late response new wires and plugs bout 500 miles ago rebuilt motor with round 3500 miles on rebuild ran find untill that happened. So you think i should change the plug again and go from there

lt1pwr1

iTrader: (1)

Ummm, why was the MAF and CAM sensors unplugged in the first place? You said you popped the hood and noticed they were unplugged...? Either way, make sure they are plugged in and restart the car, clear the codes and go from there. And don't change the plugs again if you just changed them..waste of money and time.

14k

The MAF cam (came) unplugged.

Jayday

maf was the one that came unpluged not cam i have reconnected it and cleared codes and problem persist before all this the p420 code was coming off and on would that cause the random misfire

c-ham

when i bought my car it ran like total *** idled great but at partial throttle it would drop multiple cylinders, however unplugging the maf made it run much better, so i spent $6 on a can of MAF cleaner at autozone and spayed the maf of and it has ran great ever since. first thing i would do is put plugs in it, also check into o2 sensors.

Jayday

would the cat make the random misfire code come on ?????

blade2222

A failing o2 sensor will cause this. When they start failing they will not always set a code.

c-ham

that is what i was leaning on but didnt want to say something stupid, i had a buddy at work have this problem on an old 4.3 beat up chevy truck and just as a test i unplugged hi o2 sensor, its been a year and still unplugged lol

GMtechmatt

P0300 is general misfire meaning multiple reasons from the cause, check sparks plugs, ohm out the wires, and check MAF readings and fuel trims

7camaro7

iTrader: (15)

Make sure all exhaust bolts under the hood are tight. I had an exhaust leak at one of my a.i.r. ports and my plugs on bank 2 all fouled. Killed some coils too. Swapped in 8 new plugs and coils, cleared code, it ran perfect and code never came back.

7camaro7

iTrader: (15)

Make sure all exhaust bolts under the hood are tight. I had an exhaust leak at one of my a.i.r. ports and my plugs on bank 2 all fouled. Killed some coils too. Swapped in 8 new plugs and coils, cleared code, it ran perfect and code never came back.

Jayday

i unhooked my 02s and erased code and runs good now no misfire code just p0140 and p0160 o2 codes thanks for the direction to go. Does anyone know how to adjust the two cables that connect to throttle body and transmission i think

Jayday

code came back any other suggestions on where to check