P302 and p0137 help

[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

 

[clkelley]

Welcome to the neighborhood!

I would first check the wiring leading to the O2 sensors on the passenger side of the exhaust as this code is for a catalyst issue on bank two. That being said, if the wiring is good, I would then consider replacing the O2 sensor behind the catalytic converter or check the exhaust for possible leaks, etc. Depending on your mileage, you may want to go ahead and order all four O2 sensors and take care of them now wihle you are performing maintenance on it. But the P0300 can also come from the same sensor. So that is where your problem is coming from.

 

[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 .

 

[clkelley]

It is the O2 sensors OR the catalytic converter itself is clogged. If you have one available that can do so, have the catalytic converters flow tested to determine if it is the cats themselves or the sensors.

 

[uk tahoe]

i have no cats had them removed , would an o2 sensor cause a misfire on one cylinder though ?

 

[clkelley]

hmmm, now you tell me...lol Yes, a bad O2 sensor can cause just one cylinder to misfire.

 

[uk tahoe]

hummm i might just replace all of the o2 sensors and see what happens lol £200 i dont really want to spend lol

 

[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 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