ES3

I just began noticing a a problem with my ES. It's kind of like the engine begins to stall, just a little bit. It's rather subtle, but definitely noticeable. I had the spark plugs and wires changed at 75k, the car has about 112k on it now. It doesn't sound like I'd need to change them again already. Could this be signs of my aging timing belt, which I know needs to be swapped?

Actually I began noticing the problem after I switched to premium fuel for a few tanks, just to see if there was any better performance. It's almost as if the engine was used to the low octane for the past few years, and I messed things up by upgrading, now back on the low grade I still notice it. Any suggestions???

lexusk8

You mention that you have used low octane fuel for some time before switching to premium. You might want to start trying out the easy solution and insert some fuel cleaning solution into the tank. There are many brands for this kind of cleaner like STP and such, but I highly recommend the Chevron w/ Techron concentrate. It's used by many others (including myself) in this forum, and you can get them for about $5-$6 at any auto parts store. You will have to wait after at least the first 2 fill-ups to observe any change with your engine start-ups.

If this doesn't work, then my guess is one of the following:

- fuel filter needs to be replaced
- bad fuel pump ECU
- if the timing belt has never been changed, do so now (although that won't directly affect the fuel delivery system)

Hope this helps

ES3

I've tried some of the cleaners, so my guess is it's your other suggestions, any idea how expensieve the first two are?

THanks!

DaveGS4

iTrader: (2)

LexusK8's suggestions are good ones...

Have you ever replaced your 'aging timing belt'? I don't know the maintenance schedule for the ES, but isn't it normally at 90K? Other than that I'd suspect something in some part of the fuel delivery system from your description.

squarehat

Dave is correct, the timing belt should be replaced at 90K.

lexusk8

For the '97 ES, the fuel filter is about $30-$35, and the fuel pump costs about $245 at the local Lexus parts dept.

Do you get any warning or CEL lights up in the gauge cluster when you run into this problem? It's hard to pinpoint exactly the source of the problem with the stalling of your engine start-ups, so if the cheap solution route has already been done and unresolved, I suggest bringing your car to the dealership and have it diagnosed. Have the error codes scanned if you do have warning lights pop up. Tell the technician what you have done and what you think could be the problem, and that will make life easier for him to target the problem

steviej

iTrader: (1)

two other areas to suspect would be 1. carbon build up on the idle air control assembly and 2. a dirty throttle body.

Very common with high mileage 1MZ-FEs.

steviej

ES3

Thanks for the suggestions, unfortunately, no lights on the guage cluster turn on, while the car begins stalling a bit at hwy speeds. I just added some STP fuel line cleaner treatment. Will see if that begins to make a difference. My concern is that SUDDENLY the stalling will become severe enough to immoblize the car altogether? Guess I'd better stop trying to nickel and dime it, and just hit the dealer with an open checkbook. I'm sure I'll get screwed?

ES3

Well a few stp treatments and high octane gas fill ups and STILL the problem persists, if no warning lights are coming on, would a full diagnostic at Lexus even isolate anything? Do I just need to let the problem get worse until eventually I'm stranded on the roadway?

lexusk8

Never, ever let a problem get worse once you suspect one.

If you feel you have done all you have tried to resolve the problem, bring the car to the dealership for peace of mind and let the service dept do a diagnostic. Most of the time they can detect sources of problems we can't. You might have to fork over $80 more or less for the diagnostic, but it will be well worth it in the long run.

ES3

I agree, but I'm a bit bummed that the tech. I rode with couldn't detect it and wasn't sure if a diagnostic would either? Guess it couldn't hurt, for 80 or 100 bucks.

lexusk8

That's the spirit bro

Keep us updated, whether you or the dealership has fixed the problem, as we can all learn from it greatly.

steviej

iTrader: (1)

[QUOTE]Originally posted by ES3
[B]Well a few stp treatments and high octane gas fill ups and STILL the problem persists,[B]

That isn't going to clean the trottle body or the IAC.

sj

ES3

[QUOTE]Originally posted by steviej
[B]
Any idea what will??? By the way, what's the IAC??

steviej

iTrader: (1)

IAC = Idle Air Control assembly. refer back to the begining posts in this thread.

briefly and roughly explained:

To clean these you will have to physically get at them. To get to the Throttle body, you have to remove the large hose that goes from the air box to the mechanism that holds the butterfly type valve (this is the throttle body). Soemtimes this area gets sooted up with carbon and junk. This garbage restricts airflow here. If you buy a spray type throttle body cleaner, make sure it says "safe for oxygen (O2) sensors" on the can.

The IAC is a separate assembly, usually bolting onto the bottom of the throttle body. It has a plunger or piston that allows for control of air passage when the car is at idle. Sometimes this plunger mechanism gets crudded up with carbon and gunk. This crud limits the movement of the piston and thus causes problems. The aperature and piston has to be cleaned so that total free movement is restored which in turns allows for better control of air movement at idle.

steviej