help with 98 rodeo

[badger6]

1st problem is that I notice a high pitch whine coming from under the vehicle between the front and back doors on the driver side of the vehicle. I am inclined to say that it is the fuel pump, but I know nothing of these things. It seems to get louder as I drive it longer, but you can only here it while outside of the vehicle at idle.

2nd problem is that there is a valve clatter or tapping upon acceleration or when accelerating on the highway. The funny thing is that it only happens at a certain throttle position or RPM. It happens with only a little throttle applied, looks to be around 2000 to 2500 RPM. If more or less throttle is applied (or when the tranny changes gears) it seems to go away. Sometimes it is very noticeable, other times it is not. It seems the longer that I drive the louder it gets. It doesn't happen in neutral when reved only with a load on the engine. Don't know what it is, but I know that it doesen't sound too good.

3rd problem is that yesterday while in park and running, I noticed that it was a little rough at idle and a little motor vibration (kind of like a low idle speed). Today, I noticed the same rough idle and then I look down and the check engine light is on. So what to check ?? Any ideas would be appreciated.

PS - I checked the oil a few weeks back and there was none on the dip stick. I added 1 Qt and checked it again and it showed full. Should the difference between full and not even touching the stick only be 1 Qt ?? Just seemed funny to me. This has happend more than one time.

Thanks,

Badger6

[amigo-2k]

1st. No real clue. Maybe an exaust problem?

2nd. Sounds like you have engine PING. Solution is to use a higher octane gas or clean the following: EGR, EGR port, PCV, Piston rings. The piston rings can be cleaned by adding a half can of seafoam to the oil.
http://www.geocities.com/endre_rl/isuzufaq.htm#faq3

3. Sounds like a classic Intake manafold gasket problem (autozone will read your CEL for free or buy a code reader for under 100 bucks).
http://www.geocities.com/endre_rl/isuzufaq.htm#faq5

That high pitched whine could be from a hole in the intake gasket.

PS: watch your oil like a hawk! here is how to decrease your oil use:

http://www.geocities.com/endre_rl/isuzufaq.htm#faq4

[badger6]

WTF !!! Now today after a 10 min drive to work and a 10 min drive to the post office at lunch, the CEL goes off and it runs almost normal, just a little rough, not even enough to notice, maybe just my imagination. I talked to a service advisor at an old isuzu dealership I used to work at and he told me that the egr valve may have been clogged and corrected itself. He said that if the CEL turned off and it is running close to normal not to worry about it. Well should I not worry about it anymore unless it happens again ???

Also he said that the clattering valve sound on slight acceleration (between 2k and 2.5K RPM) is probably from 87 grade gas. He told me to use mid grade gas and to put in some STP gas treatment. The owners manual says to run 87 grade. Will it hurt to run 87 grade ???
Will the valve sound cause a problem in the future or is it just annoying to listen to ???

He had no idea about the whining sound coming from under the vehicle, He said maybe the alternater was making the noise, but that it was on the passenger side of the vehicle, not on the drivers side.

Any other suggestions would be greatly appreciated.

Thanks,

Badger6