Hi Friends,

Car was random misfiring. I Ran the codes at Autozone and came up with p1448 (bad Canister vent control valve).

HOWEVER, i took it to my mechanic (who's pretty dayum good--porshe, audi, nissan mechanic for 30+yrs)) and he said he doubts the misfire is from Bad Canister valve. IN FACT he said he's changed dozens of Bad Canister Valves and never had any affect on misfiring?

QUESTION: Does bad Canister Valve have anything to do with Motor Misfiring?

Thanks for your constructive input...




~M

 

I have to agree with your mechanic. P1448 is part of the evaporative system controls. A lot of us have had that code but did not have any mis-firing.

The DTC codes are for things that can be monitored electrically. If it is a mechanical problem, a code will never be generated.

When was the last time you changed the fuel filter?

 

^^^what he said. I've just finally got done with the fix for my P0441 EVAP code in another car... it had nothing to do with misfiring, although it did run a little rougher, plus fuel economy and power got dumbed down by the ECU because of it.

 

coil pack

 

Check the area the gas cap screws on to. Any rust on the lip?

 

A car could never have two unrelated problems simultaneously going wrong with it, never

 

Whenever I read about misfire, most of the time the solution is somewhere near coil packs and EGR system. I vote for cleaning EGR tube and checking EGR valve.

 

EGR does nothing unless valve is stuck open and it's only applicable to '00.

 

For the P1448 I'd be looking at the gas cap seal, and the purge valve and associated tubing somewhere near the intake. A random misfire would be caused by something else, a P0300 code should be saved. What I have found fooling with my project 03 Maxima is the coils are 2 piece. The extension to the plug can get a bad connection to the part that screws on to the valve cover (I'm not sure there are correct names for these). I used some bulb grease at the connection between the two, so far so good. If oil burning is so bad as to clog the catalyst, assume the plugs are fouled. That will surely cause a problem. Pull them out, spray with carb cleaner, put back. Find out which cylinder is worst. This includes taking the intake manifold off to get to the back 3 plugs, which is easy work. Replace the upper and lower Intake manifold gaskets while you in there. Its all easy stuff to do, I wouldn't pay for it. If you haven't yet, remove and clean the TB. Removing is the best and easiest way. cleaning a TB on the car just isn't as good.

You might get lucky and a few cans of Techron concentrate plus or https://www.walmart.com/ip/Gumout-Mu...16-oz/43913005. They have a cleaner called PEA which is known to help with sticky EVAP valves.

If you're not hands on, can't do what I described above, dependent on mechanics you don't trust, maybe its time to move on from that car. Something newer that doesn't require as much maintenance. Oil burning is slow death. Maybe its time to let go.

 

I'd be concerned about the EVAP code.
If it was a misfire you may get a code P0300-P0306.
If it's a bAck fire you may not get one.
Mostly check the fuel pressure because it's very sensitive right?
And probably bad coils too could cause that.
I think when they say bad coils they mean the spiral cable contacting the plug goes bad.
I have a backfire sometimes too I've been chasing. It backfires only during acceleration under a load occasionally. No code either.

 

Sometimes its a fuel trim thats too rich. You have a stock or aftermarket oiled air filter? Burn oil? If so could be a dirty MAF

 

MAF has been cleaned,
Maybe it's relearning the fuel trim after the cleaning.

 

Should take a couple days depending on how much use car gets