98 s70 t5 multiple codes po133, po422 etc

[Nikkid5479]

hi need some help please.
im getting codes po133, po302,po303 po300 and p0422. i have a reader so i know what they mean but i am actually very stumped. i have given the car a tune up including plugs , wires, dist. cap, rotor, crank seal,and air filter. the car usually gives me the code for large evap leak (because i cant find the damn leak) but when the cold weather hit all these other codes appeared. Car is weak when it first starts up also. i believe my pcv is clogged because it is leaking in the top of the motor under the cover and i have already replaced the oil cap.

1) is it possible these codes are because of the evap leak?
2) po133 means slow response in bank 1, is that the front or back 02 sensor?
3) if ive already done a tune up what else could be wrong if my cylinder 2 and 3 are misfiring? bad plugs? bad coil?

any response is appreicated. i have already looked everywhere for info and the best i found was its might be possible to have a leak in the hoses around the intake manifold? could that be because of the pcv since the end of the hoses is under the intake manifold?

thanks

[Ozark Lee]

P0133 is the front sensor.

What did you use for spark plugs and spark plug wires? When I did my first 850 tuneup I used the Bosch +2 platinum plugs (which can't be gapped) and had horrible misfire codes. I have also had trouble if I used other than Bougicord ignition wires. The gap on the spark plugs needs to be 0.028 and error on the tight side.

...Lee

[dosbricks]

PO422 cat code was possibly set as a result of the PO133 sensor code. How long since the front O2 sensor was last changed? If it's the original, it has definitely outlived its useful life and should be replaced as soon as possible.

[Lucie31]

My multiple misfires were finally fixed when, after replacing the plugs, plug wires and distributor cap and rotor button, we found a fault with the cam seals. This fixed the misfire codes. Since then, the manifold seals have been replaced, and the car ran unbelievably well (thank goodness for cruise control) without a CEL for months! The only code now is p0422. Since the gas mileage is actually down by about 40%, my next step will be to ask about the o2 sensors. I love this car, but I'm not sure it would have made it through last winter with someone less stubborn, and definitely not without the help of my awesome mechanics.

[sleddriver]

I would suggest researching & reading on MVS first, as there is LOTS of info archived here. There is a current thread on Large EVAP leak. I don't know what those codes are off the top of my head. The oil cap gasket is a common replacement item. It gets hard and shrinks over time, and thus leaks. The gasket is avail. separately.

You didn't mention the mileage. Are you the original owner? Has the PCV system ever been serviced?

The easy way to find leaks is to smoke the intake manifold. I learned that lesson the hard way......should have done it YEARS ago. I would also suggest checking the two check-valves up front near the radiator and the seal at the vacuum tree on the intake manifold.

[nico416]

I spent over 1k chasing this set of problems. ended up being literally everything. Almost as if my car was booby trapped. Lol.

New sensors, np

New spark plugs, wires ect. np

Manifold leak too? New flex pipe. acordian design fail.

The rest went away, I got a purge valve code which i fixed but honestly po422 is my cars nightmare never went away

I have to now buy a cat

#99005HM magnaflow is apparently the best option that wont break the bank. Much better than buying the bosal that fails they tell me.