VX sat for a while, now won't idle, runs irratic

[mybirdcanfly]

The VX runs like total crap until it gets warm, then after warm it barely idles, sounds like its off. Believe it or not the gas mileage has not gone down that much since this has happened. Just prior to this getting this bad it ran fine but the idle was very high, which made me think it was the idle control.

But, so far I've replaced the manifold pressure sensor and idle air control valve, nothing changed.

From Rock Auto the following is also available, what would you suggest and in what order, thanks

1. MAF (By the way, any to recommend for better performance, or better gas mileage)
2. EGR valve ($130 at Rock Auto, not cheap)
3. Knock sensors
4. Oxygen sensor
5. PCV valve (would clean but I can't find it, that would help)
6. Throttle position sensor

[etlsport]

Re you getting a check engine light? That it would help diagnose it...

I would look at the fuel filter and fuel pressure regulator

[alterastro]

Vacuum leak on the inlet manifold gasket???

[VX KAT]

5. PCV valve (would clean but I can't find it, that would help)

Not sure if you're saying you don't know where the PCV valve is located, but if you are, here's a good pic (I think from LDub, in another thread).

It's right immediately above the red thing on valve #2 (which is the one on the right closest to front, closest to those blue & green things in pic). See that slight raised BLACK area on the engine cover, immediately above the red thing? The PCV is right under that. Just take off the engine cover & you'll see it.

http://www.vehicross.info/forums/showpost.php?p=87661&postcount=23

[LiquidVX]

I was going to say vacuum leak also.

[Sprey]

If its been sitting for awhile. you sure the fuel is all clean and the fuel filter is not cloggy?

might pay to replace it.

[VCrossfan]

Also check the Engine Coolent Sensor. Located that the front right of engine right below the throttle cable, a 2 wire unit thats takes a 19mm wrench. Helped mine mainly when cold...

[mybirdcanfly]

OK, I overlooked the obvious.
After putting in the first 2 sensors I took the PCV out, sprayed with gumout.

The engine light went from flashing on and off to a constant on.
It ran much better on the ride home, could almost idle, and went back to the original high idle.

BUT....a new thing has just surfaced...the shifting from one gear to the other is like a sledge hammer....NEVER had this before....what's up with that????

I'm starting to think that this is vacuum related, otherwise why would that shifting be so off now.

[etlsport]

the flashing check engine light is almost certainly because of an engine misfire.. if its slowly improving i would probably chalk it up to bad gas.. have you tried heet or something similar to remove water from the gas?


the trans sounds like a separate problem with the mode selector switch, more than likely you will see the indicator lights on the dashboard flickering or switching between gears even when you arent touching the shifter, this is a common problem and easily fixed from what ive seen (havent done one myself, but would be willing to help if you wanted to bring the VX down my way)

[alterastro]

OK, I overlooked the obvious.
After putting in the first 2 sensors I took the PCV out, sprayed with gumout.

The engine light went from flashing on and off to a constant on.
It ran much better on the ride home, could almost idle, and went back to the original high idle.

BUT....a new thing has just surfaced...the shifting from one gear to the other is like a sledge hammer....NEVER had this before....what's up with that????

I'm starting to think that this is vacuum related, otherwise why would that shifting be so off now.

Sounds kinda similar to my problem.... http://www.vehicross.info/forums/showthread.php?t=17405

Not had chance to fix yet, but have got a new inlet gasket and will be replacing that soon.

Fingers crossed!

Nick