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P0420 and P0430 and today a P0304 too.

3K views 8 replies 2 participants last post by  85ltdcrownvic 
#1 ·
This is my 1st Ford ever, so I'm a little behind around here.

This '02 CV Civilian has a fairly freshly rebuilt motor. I'm unsure if any other parts were replaced when the motor was rebuilt.

After driving it for about 1000 miles I noticed 1 day that the CEL light was on. So, I plugged in my bluetooth ScanTool scanner and discovered both a P0420 and a P0430 code. It cleared and went a while before returning.

I took it on a 2500 mile trip and received the code once about half-way. That might have been the time it was only P0430.

Today, I left the house while it was raining and splashed through some puddles and after a while I had a CEL light. Checking revealed the 420/430 codes, but also the P0304 code.

I read one thread about possibly leaky manifold gaskets. Also maybe bad cats. Are there 2 cats?

Anybody that could help me get started fixing this would be greatly appreciated.

Thanks,

-Kyle
 
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#2 ·
Do you know how old your spark plugs are? If you have access to a lift, pull the o2 sensor connectors off and check for water, that could be the problem. Since there is a misfire on cylinder 4, youll have to check that cylinder for spark and fuel.

First, let the car idle and check for any odd sounds around cylinder number 4 (passanger side last cylinder). Then check for exhaust leaks by listening for ticking noises coming from under the car. There is no consensus on what causes this code so youll have to check around. If you can, datalog with a scan tool. Do you have an elm327 scanner?
 
#3 ·
Thanks for helping!

I hope the spark plugs were changed when the motor was rebuilt about 5000 miles ago. Not sure though...Maybe I can find out.

Can I post a link to the log file from my ScanTool/Android OBDLink this way?:

https://drive.google.com/open?id=0B1ZErynM2kbfVVVwQUl1V1hZeUE

I've never set any of the 'logging' parameters since I plugged the scantool in, so I'm skeptical about what was logged. (Edit: If it matters whether I was going N/S/E/W, then that it is well logged in that file...) What should I be logging to help?

Thanks!

-Kyle
 
#4 ·
Pull all the plugs and check them. If you want you can put a vacuum gauge on one of the lines to check how your car is running.

The parameters youll want to datalog would be ignition timing, short and long term fuel trims for both banks, maf voltage, throttle position, load and o2 voltage for all 4 o2 sensors.

That datalog doesnt say anything other than speed and direction lol. If you need help eith post here or pm me.
 
#5 ·
Pull all the plugs and check them. If you want you can put a vacuum gauge on one of the lines to check how your car is running.

The parameters youll want to datalog would be ignition timing, short and long term fuel trims for both banks, maf voltage, throttle position, load and o2 voltage for all 4 o2 sensors.

That datalog doesn't say anything other than speed and direction lol. If you need help eith post here or pm me.
I 'ticked' a bunch of logging parameters in the OBDLink software and have a bit of running around to do today. I'll post a new log later.

Since the 2500 mile trip, just about every time I get in it, it runs poorly when cold, will cause the CEL light to flash and usually sets the CEL after a bit with the P0304. The P0420/430 hasn't returned in a while (I suspect that's a separate issue...). After it warms up, the CEL settles down after I've cleared it a few times, but a 'miss' can be felt.

Thanks,

-Kyle
 
#6 ·
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