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JHarris1385
01/16/2007, 03:56 PM
Ever since I have had my VX I have had an idling/misfire problem. I have been very patient with it and have tired almost everything.

My symptoms are:
To start the VX I have to depress the gas every time, while turning the key.
I have a slightly abnormally low mpg.
I emit more than normal exhaust
**Check engine light comes on*** code P0300 – Engine Misfire Detected++ This is THE PROBLEM.


I need help to solve this problem!


What I have done/replaced thus far.
1.)Brand new MAF sensor. (still have the old one and think it works fine.) (PepBoys diagnosed it and said that was the only problem with my VX.)
2.)Replaced spark plugs to NKG 5456…other than the back right one so far
3.)Cleaned the EGR by spraying choke cleaner into the small hole with the engine running. (Made sure the pindle was working properly. But noticed that the underside of the EGR valve seems like there was metal flakes on it. Any suggestions what that is>) Is there supposed to be any type of non metal gasket here?
4.)I have sprayed electric circuit spray into each plug/connector visible/reachable.
5.)Changed the PCV valve with my two oil changes so far (I have only had the VX since Sept. but I changed the oil to full synthetic, and read when doing so change the oil and filter once and once again after about 1,500 miles because its going to be extra dirty.)
6.) Changed the fuel filter


I think that is it so far. It costs me a bit so far, more time than money really

I do have the ScanGuage hooked up permanently, so information is available to me. For SG users I do have the PIDS written down but do not know if that would help or what they mean?

While cleaning the EGR I did notice a lot of carbon build up. I would like to open up the top of the engine and clean it out. How do you do this and how easy and safe? I am afraid of taking it off and not being able to get it back on. Is there a how to on this?


What DO I DO NOW????

JHarris1385
01/17/2007, 01:07 PM
bump

dkmiller68
01/17/2007, 01:58 PM
are the plugs all firing? run engine for 1 or 2 minutes then feel each one. oops, just realized they are set too deep to feel...um...how about one of those inexpensive little testors that you hold near each spark plug wire and the neon bulb would glow if it is functioning correctly...um...no spark plug wires...somehow determine if each on is firing ...how about ampmeter in circuit to each coil?

etlsport
01/17/2007, 02:03 PM
fuel pressure regulator? maybe youre running really rich so not able to burn off all the gas into the engine = misfire?... lots of vxers have had to replace their FPRs (including me) dont know that your symptoms are perfectly inline with the common ones for the FPR replaced.. but one of my issues was bad starting and i found that giving a little gas on start up helped that.. so maybe? im talkin out of my hind quarters right.. but its worth a shot.. they sell for about $50 new i beleive, DIY install

JHarris1385
01/17/2007, 02:05 PM
Wheres the best place to get a FPR? St. Charles?

etlsport
01/17/2007, 03:09 PM
heres where i got mine

http://www.drivewerks.com/cgi-bin/ppexpress/ppe_drivewerks.cgi?command=show_part_page&YEAR=2000&MAKE=IS&MODEL=VEH--001&Category=C&esc_part=Fuel+Pressure+Regulator

JHarris1385
01/18/2007, 09:40 AM
Does a faulty FPR cuase misfires normally? I do belive I am running to rich. Lots of exhaust and loss of mpg. Does a FPR fail due to the car sitting to long without use? I think the previous owner rarely drove the VX. I recall him stating he only put less than 10,000 miles on it in two and a half years and only about 350 in the last 6 months.

etlsport
01/18/2007, 10:12 AM
i think just generally they tend to fail on the VX.. dont know why but if you do a search you will find that many of us have had to replace them

JHarris1385
01/23/2007, 05:06 PM
Is this certain to fix my problem or just a guesstimate?

Any other suggestions?

etlsport
01/23/2007, 05:40 PM
nothings certain of course... but for 50 bucks its worth a shot before you go spend even more at a dealer

deermagnet
01/23/2007, 05:51 PM
I know you don't have an Isuzu Tech 2 scan tool, but you may find
something helpful here from the VX repair manual.

Mark

http://www.wtv-zone.com/markg/imags/p0300a.png
http://www.wtv-zone.com/markg/imags/p0300b.png
http://www.wtv-zone.com/markg/imags/p0300c.png
http://www.wtv-zone.com/markg/imags/p0300d.png
http://www.wtv-zone.com/markg/imags/p0300e.png
http://www.wtv-zone.com/markg/imags/p0300f.png
http://www.wtv-zone.com/markg/imags/p0300g.png
http://www.wtv-zone.com/markg/imags/p0300h.png
http://www.wtv-zone.com/markg/imags/p0300i.png
http://www.wtv-zone.com/markg/imags/p0300j.png
http://www.wtv-zone.com/markg/imags/p0300k.png

JHarris1385
01/25/2007, 03:44 PM
So it looks like I am going to buy this fuel pressure reg......and check the injectors. But I am not mechanically inclined thus far, where are the injectors and what do they look like?