Recently my 2001 4runner has been misfiring ,I pluged it in to get codes it reads

P0300/random multiple cylinder misfire
P0303/cylinder 3 misfire
P0306/cylinder 6 misfire
P0171/system to lean
P0420/catalyst efficientcy below

Anybody experienced enough to know what may be causing this ?

Oh and sorry if I dint post this in the right area . Please help thanks

 

Clean the maf and change the upstream 02 sensor. Change the plug and wires.
That's what I'd do first at least.

 

Yeah I cleaned the MAF sensor with brake cleaner , still dint fix the problem so I will change plugs and plug wires , I have changed the plugs 2 years ago but never did the plug wires , does a 3.4 litre have a distributor cap ?

 

UHHHHH, by doing that you completely killed the MAF. Those things are sensitive and they need MAF cleaner that can be found at the parts stores.
Time to buy a new one from Toyota or go the cheaper route and buy a low mileage one.

Plugs need changing ever 60K, best to change the wires with them too.

The 3.4 does not have a distributor, it has coil packs.
I think you have individual coil packs at each spark plug.

 

It's sucks if I killed my MAF sensor but nothings changed from before I cleaned it to after