nova1313x

Ok, My Beloved 2000 E320 wagon threw the cel and started running real rough. Shifting irratically due to power fluctuation. I am only getting one code P0303 misfire on cyl. 3. Code reader says most likely problems: Cats, MAF, Plugs.

I have replaced the MAF with an aftermarket and it is running a bit better. Then I pulled the plugs from cyl 3 and they were very dirty, I swapped the plugs and coils with the adjacent cylinder with no change, still misfire on cyl 3. Note, I did swap wires due to the longer wire on cyl 3 so the wires were not tested.

I did the cat test by tapping them with a rubber mallet, the rears are making a slight rattle but no cat noise when running.

So my question is: can I just delete the rear Cats? I am planning on doing a full plug and wire replacement, and contemplating getting the OEM MAF. It seems like I am not getting any spark on Cyl 3...I am really confused, would a bad Maf shut down ignition on one cly?

The car has 173k on it, but was running like new before this started.

OH Lord please help.

Plutoe

Who gave you the rear cat idea---amazing--you are better off checking your tire pressure, in any event------Use your scannar to get the cylinder freeze frame data then do the associated fault test on the cylinder before you start to purchase anything!!

Hirnbeiss

Clearly you want to test the wires, too, before moving on. If that isn't the culprit, I would look to the injector next. A plugged cat would affect all cylinders.

nova1313x

I just have a regular OBD code scanner. What would freeze frame data show me?

Thank you. it does seem like I am getting fuel because when I pulled the plugs they were wet.

nova1313x

I replaced all pligs and wires. engine smoothed out and seems to be driving fine.

after driving for about 60 miles I turned the ac on and the CEL came back on. I did replace the MAF when this all started happening with an aftermarket unit from ebay. Anyway, I unplugged the MAF to see if there was any difference in how the engine was running, and the engine cooling fan kicked on. The engine is running fine but the cel is on, and it is running a little hot (is was 91% today outside).

my question is: does the maf affect the engine cooling fan, which would in turn cause the engine to run hot and a throw a Check Engine light?

it's either the MAF or a CAT issue. I did go to autozone and have it scanned after tuneup with no codes, but it did say engine had not gone through complete cycle yet.

i was so relieved after tune up. but I am now thinking this aftermarket maf needs replacement which is my hope, or the misfire issue i was having due to bad wires on cyl three causes the cat to melt. the thing is, it is idleing very smooth, and does not seem to be misfiring at all.

please help...oh lord, are you out there?

Plutoe

That is not a function of the MAF

The aux cooling fan comes on because you engine coolant is above 103C or the refrigerant temp is to high(I forgot the value).

Once again you are grooping at straws-----forget about the shoulda woulda replacement ideas------read the codes----what is the new code.

Don't replace anything untill you fine out what's the fault

nova1313x

That is why I was asking about the MAF.

I am on a mission not to spend any money on hourly rates!

It is also suspect that whenever I disconnect the MAF, the cooling fan comes on.

Believe me, I don't want to waste any money on unnecessary parts. I just want to prevent any further damage. The car is running really well, I think.

Is slightly above 80 on the interior temp gauge normal.

Thanks.

Hirnbeiss

What was the code that returned after your 60-mile drive?

nova1313x

i put the aftermarket maf back on and cel went off the popped back on after about another 30 miles. The only trigger for the code seems to driving with ac on.

so if i am getting a p0100 when engine is hot, what could be the cause? the car is driving well. shifting still seems to be a bit hesitant but i just did a soft trans reset.

Plutoe

You have had so many issues, I am just baffled!! anyways

Based upon what you have written, the P0100 is the MAF fault-----Do us all a favor, clear the fault and use the car without turning on the AC----does the fault return???

mb techman

.

nova1313x

----- How do you think I feel?

I am humbly asking for help. The only way I know how to clear the code is disconnecting the battery. the scanner does not allow me to clear codes. Will a battery disconnect clear the code?

To be clear - I am asking for an educated recommendation on whether or not I should spend the money on a new OEM MAF. Or how I can come to that determination.

And yes I have had the misfortune of having a few issues at once that I have successfully fixed. I am now down to one.

btw, I look forward to share my experiences with others on this forum who have similar issues in the future.

thank you for your help.

Hirnbeiss

Agree with Plutoe's recommendation to drive without the AC for 60+ miles.
If the light stays off, but then comes on later when you turn on the AC, this points to a problem with your electrical wiring since AC has nothing to do with the MAF. You will have to troubleshoot that with new MAF or not, so I would work on that first.

nova1313x

Even with the airflow code,(i.e., p0100)?

I am just gonna get a new MAF. I am driving with a 25 dollar unit I bought on ebay. I shouldn't have bought the cheap unit, and never will be comfortable that it will last and operate as it should.

Amazon has the Bosch units for 119.00 w/ free shipping. In the review, a reviewer states genuine Bosch. If the box has hologram then I should be ok.

Thanks for your help guys, I will let you know the outcome.

Hirnbeiss

That sounds like a plan.
Once the code is cleared, then do the long drive without AC.