VX Starts ok, but runs terrible...

[l.ectric]

Hmmm.. well, I'm new to the whole VX thing, and I've got to say that you all are the nicest group of people! Anyway, I bought a 99 VX last month and had to tow it home because it was running really bad.
Here's what happens when I start it up:

Runs ok for first 15-20 seconds, then starts to idle rough. If I give it any gas it revs slowly then wants to idle very low. Almost no power at all when I put it in gear and try to drive it. It "pops and coughs" when the gas pedal is depressed.... Also, there is a strong hissing noise coming from the throttle body area, which leads me to believe that it might be the IAC motor... even though I did pull it out and looked to be funtional when turning the key in the on/off positions multiple times. Could it be the MAF? MAP? O2 sensors? Plugged CAT? Timing? I'd love to see if anyone else has had this problem. Thanks a ton in advace!

[MSHardeman]

Sounds like it's starving for fuel and/or air. Don't know how many miles are on it, but maybe replace the fuel filter and the fuel pressure regulator to see if that helps. I know when I replaced my fuel filter at 60,000 +/- I could barely blow through it so it was pretty clogged.
This might be way off, but have you taken a look at the air filter? Is it clogged and not allowing the VX to breathe?

Oh, almost forgot....welcome to the family.

[tom4bren]

Yes, welcome to the family ... and to the adiction.

I'll second what MS said. Start with the more simple solutions and work upward from there. Most of that should probably be done anyway.

Replace the fuel filter
Replace the air filter
Clean the MAF sensor
Clean or replace the PCV
Clean the EGR system
New spark plugs wouldn't be a bad idea
Clean the Idle Control Valve
Clean the Fuel Pressure Regulator

Also don't forget to keep an eye on your oil consumption & on your CV boots.

There are threads on just about all of this. Let us know if you have any trouble utilizing the search function to find stuff.

Read this: http://www.vehicross.info/forums/sho...ntake+manifold

[circmand]

spark plugs and make sure the wires are in the correct firing lorder. PO may have tried to do a tune up or something and put the plug wires back in incorrect the order,

[newthings]

Welcome
There are about 5 of us on the coast near the Oregon Washington border.
Roy

[nfpgasmask]

The problem you are having sounds like a problem I once had. In my case though, I let the fuel get to low and the truck started running REALLY rough, SCARY rough in fact, and I got a CEL. I changed the spark plugs and that didn't help. I then went and filled up with a tank of premium and everything went back to normal. Are you getting a Check Engine Light in the dash?

Bart

[l.ectric]

The VX has 60,0000 miles, plugs are in correct order, remove the air filter, oil level looks good. I'll change the fuel filter and IAC this week and see if that helps. Thanks newthings, I'll let you know when I get it all fixed up and when I'm headed down to Seaside... it's one of my favorite vacation spots!

[l.ectric]

Yes, it comes on almost every time it is started, and it has flashed at me once.... I haven't been able to reproduce the flashing CEL, though... it was a one time thing, i guess. I'll try the gas trick... I'll drain the old stuff first. Thanks!

[l.ectric]

Awe, schucks... (No Pun Intended) I might tow it over there later today or tomorrow.

[nfpgasmask]

Exactly, if you got a CEL, you might be able to still read the code (the ECU stores it I think) even if it is not lit anymore. That would be a good start. If you have gas in the tank, you are probably ok, I just ran mine to low and I think there was some water in the fuel. Unless you are really low on gas like I was, I don't think that is the problem. I'm not sure how you intend to drain the fuel, but I would not recommend doing that unless you know you have to.

You could also try a jug of HEET fuel treatment, that should get rid of any water in the tank. A can of Sea Foam in the gas tank also can't hurt.

But anyway, get the code read, and bring the number back to the forum and we can tell you what it means.

Good luck,

Bart

[ScottinMA]

My bet...vacuum leak.

[VXorado]

My bet...vacuum leak.

+1 Thats what i was thinking since there is hissing from the engine. A vacuum leak can mess with the air/fuel mixture

[blacksambo]

Is the check engine light on? If so are you getting a 171--- OBD2 meter code? If yes, change the common chamber gaskets, top and bottom. It will run like dream. It's a very common problem and easily fixed.

[l.ectric]

Ok, so changed fuel filter and throtle position sensor and cleaned MAF... but no change in problems... next I'm going to check the catalytic converters.... weird that there are 2... the more I think about it, i wonder if the muffler is clogged?

[mrtew]

I'd clean or replace your EGR valve. That made mine run very rough and caused the check engine light to be on. Make sure it's an Isuzu one if you replace it because my dealer used a generic one and had to replace it again in a month or two. Now it runs like brand new!