Noisy idling in 1996 V6 Isuzu Rodeo

Hi,
My 1996 Rodeo (V6) makes a noise that can be described as fluttering or air compressor or diesel engine like! It has 146K miles. Last time the timing belt was changed was at 75K. Just had a tune up and so the
spark plugs, fuel filter, air filter, PCV valve are all new. Fluids and oil are all at normal levels.
When I start the car in the morning, it sounds like an air compressor starting up. After driving around for a bit, it quiets down a bit. When stopped and idling, it sounds like diesel engine and has a fluttering noise to it. The funny part is that I filled it with 93 octane gas and the noise seemed to go away for a few days but it's back now (even with the 93 octane). I live in Boston so it's pretty cold when I crank it in the mornings.
Any ideas what might be going on? The mechanic suspected that it might be bad valve covers and that replacing them is not cheap. Would changing the timing belt solve the problem
Thanks for any ideas.
Rgds, BC.
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Hello,
I currently have my '96 Isuzu Rodeo in the shop right now getting fixed for bad idling (i.e. sometimes would stall when coming to a stop or sometimes idling too high when coming to a stop). I too have had issues starting it in the morning and it sounding very odd. What I usually do is rev the RPMs to about 2k until the rough idling turns to a nice hum.
What my mechanic had just told me was that the Idle Air Control motor grinds (part costs approx. $48). Since it's grinding due to possible suit and/or carbon build up, changing it could cause some of that carbon or suit to get back into the fuel system, so their going to do a fuel system flush (approx. $120). Since they're doing that, they said they might as well change the fuel filter as well (part costs approx. $14). Labor, in my area, to do all this is approx. $80-$90, plus they have to charge me for figuring out the problem (approx. $82). Throw in tax and i'm looking at close to $400. I think I can probably get away with the fuel system flush by just putting some Red Line injector cleaner into the gas tank, but I guess since I have the money, might as well get it all done.
So you could have your mechanic take a look at your Idle Air Control motor (or even the valve) to make sure it's working (or opening and closing) properly.
I'd like to know the outcome too, because it happens far too often that these threads get created and problems asked to be solved, but no one takes the time (once said problem is solved) to come back and report the possible fix turned into the absolute fix.
Thanks & Good Luck, C
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beeker01 wrote:

sounds like low oil presure to me what does your guage say on the dash
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Sounds like a typical 3.2 Isuzu to me... :-)
Or did you mean worse that usual?
Wesley

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It sounds like the hydraulic lash adjusters(lifters) have collapsed or are sticking due to varnish build-up. An Isuzu service bulletin from 2000 (TSB SB00-01-S009) has a two step remedy.
First step;
A. Make sure engine is fully warmed up-drive at least 15 minutes to your local Isuzu dealer and buy a genuine Isuzu oil filter and the drain plug gasket. Then go to your local Wally World and buy 5 quarts of 0W-30 Mobil One oil or the equivalent.
B. While engine is still warm, drain oil completely-let it drain as long as possible. Change oil filter and gasket on drain plug.
C. Refill with Mobil One.
D. Start engine and make sure oil pressure is OK.
E. Increase RPMs to 2500 and keep there for 30 minutes(yes, you can drive it to re-cycle the old oil somewhere). If the noise diminishes then your on the right track. If the noise lessens on cold starts after a couple of days then you should schedule some time to repeat every step of this process in a couple of weeks. After your satisfied the noise level is acceptable, then you can go back to a good brand of 10w-40 oil(I use Valvoline) and do not exceed 3-4k miles before a change.
If this procedure doesn't help, then go to second step.
Second step:
A. Take vehicle to a reputable facility and have them replace the problem lash adjusters. Hang on to your wallet. Parts are expensive. If you go this route, have them change the oil pick-up tube in the crankcase. It clogs easily.
I reiterate, change oil every 3-4,000 miles!!!
Joe D

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Don't you mean 6 quarts?
Wesley

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Maybe it holds 5-1/4 or 5-1/2 but Mobil One is not inexpensive and 3-4 qts will do the job unless there's a massive leak. I've seen these engines run with 1-1/2 qts. The Mobil One is cleaning the engine so you shouldn't be keeping it in there for too long. As I said, if this improves the situation, you could repeat the process with the M.O. and a new oil filter before going back to dinosaur oil. You can top it off at that time(maybe with some Marvel Mystery Oil)
Joe D .

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Wow...you're way braver than I! :-) I like to keep it within a quart of full, but good to know it can go lower (if not caught) and likely be ok...
Wesley

your
plug
Mobil
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