VX Stalls and Dies While Driving

[Clyde]

Well, my VX still does crazy stuff when it comes to reving up. Sometimes it will rev up really high (around 2000-2500 rpm) when put into park and your foot is off the accelerator. Other times, especially in the morning while driving to work, you can be driving down the road with the tach reading 2500 rpm and then they will drop to 2000-2250 rpms for no apparent reason. You can actually feel everything ease up and run smoother after that. As far as the idling high mentioned earlier, it will happen at any time. Doesn't matter if the engine is cold or warm.

One thing that really irks me about it is when I'm stopping or in behind slow moving traffic. It wants to launch you from a stop on it's own (without hitting the accelerator) or you have to ride the brakes in behind someone driving slow (as in bumper to bumper traffic) because it wants to keep pulling you down the road. Thankfully the brakes are super strong to overpower this.

I've also checked the "duh" factors to see if my floor mats are causing the accelerator to stick down a little bit (or anything else for that matter) and checked the throttle position. Both of these things have been fine when it's having one of it's fits.

[Cyrk]

Clyde my VX has been doing the same exact things as you are describing...

It is at the dealership and it turns out it is related to the sensor on the power steering pump (Switch Kit Pressure - Part# 8971883700) that is frayed and dirty.

Called St Charles and ordered a new one to be next day to the dealership for 154.45. Should be fixed today.

Check that out, I'll let you know when I get it back if that fixes the problem.

[kpaske]

Hmmm.... I would have never associated those symptoms with a power steering sensor. Please be sure to tell us if that fixes your problem!!

[VXtreme]

Pull the throttle body as the mechanic suggested clean it throughly and ALSO clean and/or replace the idle control valve in the throttle body. I had been experiencing similiar problems for nearly a year. I replaced all the O2 sensors, purge valve, MAF, MAP, throttle position sensor and analyzed all systems and still the problem persisted. I cleaned the throttle body and idle control valve and the VX runs better then it has in over a year. No stalling, no erratic idle. I later replaced the idle control valve with a new one, about $45. From what you are saying, I would put my money on the throttle body and idle control valve. If you are concerned about the intake manifold gaskets, have a mechanic smoke the engine and it will tell you if you have a vacuum leak.

[Clyde]

Thanks for the info Cyrk and VXtreme. I'd like to know if that helped out with yours too Cyrk. In the past, I have cleaned around the throttle body plates and the lever of the throttle body, but haven't taken it off to do a really thorough cleaning of it. I have also replaced the TPS, but not the idle air control valve. I really don't believe my intake is leaking though. But I can always check that out also. What is up with that leaking anyway? I've heard a lot of users on here say they have had that problem. Was it a bad casting run of the parts or just a gasket that doesn't seal well? Has anyone went to extremes and had the surfaces redone so it will get a better seal? Are there better gaskets to use instead of the stocker? Just curious.

I've even wondered if the rpm problem I'm having has something to do with the torque converter. Since I have heard it "clunk" when going into gear that is why I wondered. I had a car in the past that wouldn't shift right and it was because of the torque converter. It made a clunk like sound when going into gear at times also.

[kpaske]

The intake manifold gasket leak is a very common problem. Isuzu put out a tech bulletin at some point changing the torque specs for the intake manifold bolts because apparently torquing them down to the original specs was causing many of them to leak.

If you want to test for the leaking gasket, it's very easy. Buy a 99 cent can of "starting fluid" from Wal-Mart or wherever. With the VX running, spray liberally around the gasket. If the RPM's go up while you are spraying in a certain area, then drop back down when you stop, there is a leak in that spot.

[VXtreme]

Clyde,
I was under the impression that you had removed the throttle body. I would highly recommend that you do that and clean it very throughly. Take the idle air control valve off and use the same throttle body cleaner to clean it throughly and reinstall. What was happening to me was the valve was sticking open and allowing excess air to enter the engine. I was getting a P0101 code which is a problem with the MAF system performance. This code does not however indicate that it is the MAF, it could be a number of things, TPS, MAF, vacuum leak, MAP, or any unmetered entering the engine.

I had been dealing with a problem you described for over a year. Three different mechanics and I tried everything, but the problem was the idle control valve, which I found on my own. Try cleaning it and see if the problem does not improve. If it does, order a new replacement.

As far as the problem with intake gaskets. It was a problem with the material they were made of, nothing to do with the casting of the manifold. The later gaskets were made of different materials and that seems to resolved the problem The older would become brittle after time and temperature and crack.

The clunk is pretty common in all the VX's and I don't believe that it has anything to do with your idle and stalling problems. I did change my fluid in my trans, tod and differentials to Royal Purple and it has made them much quieter and run cooler.

[Cyrk]

Picked up the VX today. So far so good no weird holding on the rpms. I did not get to drive it but from the dealership home, bout 10 minutes everything was smooth. I'll give a report after I get some more drive time.

They replaced the sensor and I had them clean the throttle body and idle control valve also.

But it was the the sensor on the power steering pump (Switch Kit Pressure - Part# 8971883700) that was the culprit in my case. Fingers crossed that the wacky idle does not come back.

It's worth a shot to look into that sensor if your rpms are holding around 2K rpms.

Good Luck.

-Dave

[Ruflyf]

They replaced the sensor and I had them clean the throttle body and idle control valve also.

Can anyone take a pic of the location for the idle control valve and post it today? Mine is acting up (high idle, etc) and since I am at work today I cant look it up on the disc. If someone can post a pic or describe where it is located I can take a look at it and probably clean it while at the fire station today.

Thanks

[VXtreme]

Since I have a S/C on my engine and the throttle body is mounted upside down on the S/C'd engines, the idle control valve should be on the upper left hand side of the throttle body on a stock engine. This would be when you are looking at the engine with the hood open looking toward the windshield. It is a dark gray/black domed sensor that has an electrical plug going into it. It has 2 screws (I believe they were torx screws) holding it into the throttle body. I would recommend that you remove the throttle body and clean it and not just the idle control valve. The port that the idle control valve closes against was pretty dirt with oil buildup on mine as was the idle control valve itself. I don't think that you can clean that port well without removing the throttle body. You want to also clean around the ports where the butterfly valve in the throttle body closes. I would recommend removing the throttle body. It only take about 30 - 45 minutes to remove, clean and reinstall.

[Ruflyf]

Thx for the tips, mine is s/c'd also. I'll take a look at it this evening when things slow down here a bit.

[Cyrk]

Well the weird high idle came back this morning on my way to work...
Going to bring it back to see what is up... crap.

I'll let you know what they find now. Pain in the azz VX.

Almost made it a week...

-Dave

[VXtreme]

I would replace the Idle control valve. They are only about $45 and since replacing mine no codes, no idle problems and the VX runs perfectly. Do you know that they pulled the valve out and not only cleaned it but the port it closes against? Also, did they pull the throttle body and clean it thoroughly or did they just shoot some cleaner down the throat?

[Cyrk]

I am not totally sure... I have a call into them.

[kelvin]

Maybe a hiccup in the rev limiter ?

does any one know where to find the rev limiter on the engine? or is it built into the computer?