O2 and MAF sensor question

So the guy at the shop that I trust said that when he was driving the VX and the valve clattering problem occurred he said the codes that were thrown were that the VX was running lean (I think he said 2 error codes up stream or something like that). This is an intermittent problem, that has been happening far more frequently here lately, and will eventually kill the engine after 45-60 mins of driving in a day, so what is most likely the problem?

O2 sensors or the MAF sensor?

Are O2 problems intermittent or consistent?

Where have you all purchased O2 sensors from?

Thanks. Oh yeah the problem is like this: drive more than 45mins or so = valve clatter, try to continue driving more than an hour = engine dying every 5-10 seconds, pull the MAF sensor plug and you can limp it home and the valve clatter goes away after pulling MAF plug but engine runs rough at times, but no clatter.

dont rule out a vacuum leak either.. when things heat up, things can swell up and small vacuum leaks can turn into larger ones

What He^ said.

Start looking for intake manifold leaks when you engine is already hot.

Not sure what the noise is that you are hearing though.
With our valve drive system, they are either good, or loose all the time.

Good luck with it.

PK

Ryan, Vicki has been throwing a lot of codes lately too, but she hasn't stalled out on me yet. The four codes that I have been getting are:

P0137 - 02 Sensor Circuit Low Voltage (Bank I Sensor 2)
P0157 - 02 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
P1171 - Fuel System Lean During Acceleration
P0303 - Cylinder 3 Misfire Detected

I use this site http://www.obd-codes.com/ to get all of my OBDII code information. It's super helpful and gives explanations of what the codes are, what could cause them, and possible ways to fix them.

The 0137, 0157 and 1171 codes all come up together, usually under acceleration, and the site above says that one of the solutions for all three is to clean/replace the EGR valve and MAF first. That's the cheap fix, but it could be a clogged CAT that is throwing the codes too. I'll shoot for the cheap fix first to see if that does any good.

The 0303 code could also be triggered by the other three codes although it usually doesn't come up at the same time. I've already switched coil packs from one cylinder to another to see if it was a coil pack problem (it wasn't) and replaced the spark plug to see if that would fix it (it didn't). I'm hoping that by cleaning the EGR and MAF that will fix my cylinder three mis-fire issue.

Maybe some of this is going on with Little Beast? Hope it helps......some.

Yeah, in the last couple of months I have:

-replaced alternator twice
-replaced battery
-cleaned MAF sensor
-replaced EGR valve
-replaced timing belt and all related pulleys (water pump, idler, etc)
-replaced valve cover gaskets and all new spark plugs
-replaced a/c compressor
-replaced belt idler pulley
-replaced harmonic balancer (crankshaft pulley)
-replaced power steering pump

I am about ready to give up on the LittleBeast :-(

Either I need to get rid of the VX and get something else, or I might need to find a V8 and swap everything in front of the transfer case on the VX. Either way I don't think this will be an easy fix.

I'll agree with the above statements...:_wrench:.:yes:

http://www.vehicross.info/forums/sho...3&postcount=19

http://www.vehicross.info/forums/sho...ster+stainless

The stalling could be your TPS (throttle position sensor).

did you check volumetric efficiency? Ie how much air flows through and where is the restriction?
Sound like you have cat problem - when they heat up - honeycomp expands sealing cats. so engine chokes up from exhaust side.
to confirm you can remove both 02 sensors before cats off the rig and drive around. will sound loud(you create exhaust leak), but if it does not chokes up when heats up - you need cats.

+1 on the intake manifold gaskets. That will throw a lot of misc lean/misfire codes like that... my 99 Trooper had the intake manifold gaskets go out twice in 65K miles.

I had them do the "smoke test" for any vacuum leaks or intake gasket leaks, and it passed with flying colors.

He replaced the MAF sensor with a new one and said that it is no longer almost dying on him, but it is still making the valve clattering noise.

He did say that it might be that crank pulley (harmonic balancer) that they replaced not too long ago. It was an aftermarket pulley and not the $270 OEM one.

He also said that when he is reading all the codes there is not enough info for the EGR valve, he said the computer is acting like there is not even an EGR valve at all, there is no info on it.

????? I have no idea what to do at this point. VX sounds like it is about to die, even though now it is at least not dying all the time..... :-(