Check Engine - Off/on/off/on what..

[Corrosive]

Ok so first things first... I did a search.

My check engine light came on right after I did a fill up, I then tightened the cap and a day or 2 and about 80 miles later it went away. It was off for about 2 days, then all of a sudden it came back on. I have yet to tighten the cap again, but am now wondering if it could be anything else. I assumed that if it was something other than the gas cap then it would have never shut itself off like that. I will have time on wed to take it in, but just kinda want some peace of mind untill then. Is it possible that I just need a new gas cap bc the one I am using now just dosent seal as well as it did in the past? Any thoughts or ideas will help me out alot. Thanks,
-Mike

ps. If I take it to autozone and they check whats throwing the code, is there one that says gas cap or will that read something else?

[Joe_Black]

When you tightened the gas cap did it "click" several times?

It could be an anomalous error that threw in coincidence with your fill-up too.

If you go to get it read be sure to post and we'll look it up for the shop manual equivalent and go from there.

Also, you could disconnect your battery for about 30 minutes or so to reset the ECU and see if it returns.

[Corrosive]

Yes it clicked and I clicked it an un godly amount. I think thats what I am going to do. I will disconnect the battery over night and tighten even more then see if it comes back on. If so, then to get checked for sure.
Thanks,
-Mike

[JHarris1385]

I have had this same problem since I bought the VX only about 2 months ago......The check engine light will be off for a couple days and then just stay on for a couple days and somedays it will come on and off randomly through out the day.

But I am also expeirincing rough starts and low MPG (about 13-14mpg 70% hwy driving too.) Still cant figure out the problem..

[LittleBeast]

I am having the EXACT thing happening and Autozone keeps saying it is a P0440 fault code and the Isuzu shop is still maintaining that it is probably just the gas cap being loose... Doing a search on here brings up some interesting things but none really give a definitive answer. I have already had my EGR replaced and just had the tubes connecting to it all cleaned 2 weeks ago, but maybe something is loose. It gave me the code only for a couple of days before the EGR and tube cleaning, but it has come back now. Other treads:
http://www.vehicross.info/forums/showthread.php?t=709&highlight=440
http://www.vehicross.info/forums/showthread.php?t=8098&highlight=440
Hope that helps a little as I am still trying to be completely rid of this problem myself.
In Christ,
Ryan

[Corrosive]

I have to admit that my VX has a somewhat of a rough startup and my gas milage is the same as yours, but then again I think that the gas milage is normal.

Small update ---- I didnt mess with the cap at all and today it turned off while I was on my way to work. I didnt pull the battery or anything, it just turned off on its own.

I still plan to take it in to get an oil change/check fluids/and brakes on wed so we just might find out something that is wrong.

-Mike

Beast... do you think it may be the weather (remember that we live in the same city)? Mine has only started doing this once it started to get colder?

[JHarris1385]

I have pulled the code of

po300 random
multiple cylinder misfire

at Autozone

13mpg is common?, I was getting near 18 before the check engine light.

I HAVE NO IDEA what to do with this code and no one around me wants to work on or even look into the VX

[Corrosive]

Mine went away and has been gone for quite some time now. As far as finding a shop... just tell them its basically a trooper... I find it hard to believe that they will not work on it, its not something crazy like a lambo or something.
-Mike

[Sue777]

Interesting thought, Corrosive..... my "Check Engine" light went on Saturday and is still on, and it DID just start getting cold here in Connecticut.
Sue

[Corrosive]

Long term update: It has stayed off since the last post and the weather has been off and on here. I have been looking like a moron at every fill up though, cranking it so much that everyone looks at the guy making all the clicking noise, lol. It was the gas cap no doubt and I am glad that debockle is all over.
-Mike

[VXtreme]

Check the codes and if it indicates that you have a large vacuum leak, (like a loose gas cap) it probably is the wire that goes to the purge soloniod on the gas tank. A common problem with the VX's and Rodeo's is that connection will corrode and or break through triggering the code and the check engine light intermittenly. Repair the connection.......problem solved.

[nfpgasmask]

Hey, if you are getting misfire codes, change out your sparkplugs and see if that helps...hopefully that will do it and it isn't something more serious.

Bart



I have pulled the code of

po300 random
multiple cylinder misfire

at Autozone

13mpg is common?, I was getting near 18 before the check engine light.

I HAVE NO IDEA what to do with this code and no one around me wants to work on or even look into the VX

[nfpgasmask]

I think the cold weather certainly does have an affect on the VX starting up. Mine has a weaker startup every morning since its been cooler outside. I usually let it idle for a couple minutes in the garage before I peel out down the street. Once it is warm, it starts up fine.

Bart

[JHarris1385]

So replace all my spark plugs aye? I would like to get the iridium ones but that would set me back another $60 im sure. I thought these were 100,000 mile spark pluggs? Any recommendation of pluggs to use? Thanks for anything.

[nfpgasmask]

Well, hopefully someone more in the know will reply, cause I am no expert. But I always thought that a misfire could mean that one of your plugs was bad/going bad causing the misfire. I had trouble about 2 months ago with really rough idle and a CE light. I thought it could be the plugs, so I changed them out, and still had the same issue. In the end it turned out to be bad gas and I was really low, but I did change the plugs and it was easy (except for the back right one, which is difficult to get at because of the master cylider). The plugs I bought were like $7 or $8 each, I can't remember the type/brand but I have it written down in my log book. If you want me to check let me know. Anyway, $60 ain't much to spend if it does the trick, but then again, if it doesn't?!?!?!

Bart


So replace all my spark plugs aye? I would like to get the iridium ones but that would set me back another $60 im sure. I thought these were 100,000 mile spark pluggs? Any recommendation of pluggs to use? Thanks for anything.

[nfpgasmask]

Here is a quote from a website about misfires and CE lights:

UNDERSTANDING DIAGNOSTIC TROUBLE CODES
A misfirewill cause the Check Engine Light to flash while the misfire is occurring. A misfire that occurs in a given cylinder will also set a P030X code where "X" will be the number of the cylinder that is misfiring. For example, a P0302 code would tell you cylinder number two is misfiring. But here's the important point: The code does not tell you why the cylinder is misfiring. You have to figure that out by performing other diagnostic tests. The misfire might be due to a fouled spark plug, a bad plug wire, a defective ignition coil in a DIS ignition system, a clogged or dead fuel injector or a loss of compression due to a leaky exhaust valve, leaky head gasket or worn cam lobe.

from this site (http://www.aa1car.com/library/mil.htm)

Bart

[JHarris1385]

What plugs were those. My light will go on and off every other day almost. But when it does change from off to on while idle I notice a gain in the engine and honestly I does sound like a spark had taken place.

[nfpgasmask]

OK, I just went out to my VX, this is what I have written in my log book:

NGK Iridium IX - BKR5E IX-11 5464

I bought them from Pep Boys and if I remember correctly, they were about $7 or $8 each...

Me and my buddy swapped them out, it was pretty easy if you have an extension tube for your wratchet. Except for the back right one, I remember I had to rig something up to get to the screws back there....you'll see :)

Bart


What plugs were those. My light will go on and off every other day almost. But when it does change from off to on while idle I notice a gain in the engine and honestly I does sound like a spark had taken place.