p0302 & p0137

[uk tahoe]

Hi all , im new and from england ive been having afew problems with my 2001 tahoe 5.3l , now where to start all of my problems started with the dreaded p0300 and both banks running lean .

so after alot of reserch ive replaced the intake manifold gaskets with the green ones , all plugs and leads , maf , theres no vacum leaks any where , so after i done all of this things got a little better tahoe no longer running lean but the p0300 was still comming up .

now after aday the p0300 turned into a p0302 no matter what i do with the plugs or wires and swapping the coils from cylinder to cylinder the misfire sticks on cylinder 2 .

now yesterday when i took the tahoe for a drive i noticed when on the motorway / highway if i keep my foot the gas as a steady speed the engine light gos off on its own but as soon as i let off the gas a little the light will come back on and if im driving around town the light will always be on .

so i checked the codes again when i got back home to find the p0302 still there and now have a p0137 aswell , i could really do with some help as im in england i cant just drive down the road to buy parts i have to order most parts and take 1-2 weeks to get here and dont want to be throwing money away .

the truck seems to run fine pulls fine and has no starting problems so im stuck on what else is could be any help would be great . thanks for reading

 

[gitrduun]

Mate I think you could do with some O2 sensors, both banks, you only need the front ones because they are the only ones that measure your mixture, the rear ones are for your catalytic converters

 

[gitrduun]

And the 137 code is for your o2 sensors I think

 

[uk tahoe]

hi , yer p0137 is Oxygen O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)

im not to worryed about that one for the minute i really want to fix the cylinder 2 misfire as im puzzled by it.

 

[gitrduun]

It almost sounds like a fueling issue

 

[uk tahoe]

ive reset the codes today and ive noticed it starts as a p0300 multiple misfire then after some driving turns in to p0302 cylinder 2 misfire .

 

[southboundchicken]

had a similar problem turns out i had a bad plug. i was using the bosch platinum plugs that have the cap that unscrews from the plug and as it turned out the cap was the problem so i removed all the bosch plugs and replaced with a/c delco and never had another issue. hope this helps but most importantly i hope you find the source of your frustrations

 

[uk tahoe]

well today i can now hear the misfire by the exhaust you can tell when it skips a beat really starting to hate the tahoe now lol im lost now and not a clue what to do .

 

[greenhornet]

Just a thought but have you checked the fuel pressure,55-62 psi . key on engine off?

 

[uk tahoe]

it wont be a fuel pressure problem as i have lpg system fitted and the tahoe misfires on both petrol and lpg fuels .

 

[uk tahoe]

Hi , all just an update i ordered some ac delco plugs and leads fitted them today and truck seems to start better and runs better , but p0302 now comes up all the time with this plug and lead setup when i took the tahoe for a drive the check light was comming on then going off unlike before when driving around town it stayed on all the time .

now when i go up a hill and and give it some the check light gos off weird soon as i come to a stop at the lights or traffic it comes back on , today i also unpluged my maf sensor and its idles abit smoother and the check light for maf unpluged come up but no misfire code , left it running for 5 mins to see if the missfire code poped up but it didnt with the maf plugged in check light comes on right away with misfire .

could really do with some help on this really doing my head in . thanks

 

[2003denali26]

Any update? did you end up solving the problem, having exact same problem with my 2007 tahoe, i have changed plugs,coils,swapped injector from 2 to 4, swapped wires from 2 to 4 , cleaned all injectors, took off valve cover to check lifters / rockers all good, thanks

 

[retiredsparky]

Since the problem stays with the same cylinder, you could have an injector issue, or a stuck valve that is not closing properly, injectors are a more common problem. If you pull the injector, you can verify it's operation in a simple manner by doing a youtube search for injector cleaning, using a 12 battery to open the injector and a can of carburetor cleaner to pressurize the injector. The visual evidence may help to decide if the injector is functioning correctly. Good luck.

One other possibility that is not likely is the purge valve for the evap system. If the valve stays open, the engine runs lean.

Have you changed the intake manifold gaskets? That is another possible cause.