Sup everyone,

I have had a problem in the mornings with my 01 GS430. It seems like something is going wrong. The car starts fine but doesnt idle up like it used to and seem like shes idling rough. When I leave the driveway I barely accelerate at all and she seem to fall flate on her face when I do so. When I accelerate a little heavier it doesnt seem to be as apparent. Also my RR window quit working. The switch at the drivers and the one at the rr door do not work. I am assuming it is the motor but I never use the window much anyway?? It is in the up position so I guess I am lucky there. So I have a couple questions...

1. Is there a module in the vacuum system on these cars to give us the high idle condition at start up i could look in to? or what could be causing what i have explained?
2. Could this be vacuum related or tranny related because i notice the stumble as she shifts out of 1st to second ..but it has also happened while driving down the street while still not up to temp. Once shes up to temp she seems ok.
3. Is the window just a bad motor or should i be looking elsewhere?
4. Is there a how to on here for removing door panels? I could not locate one with search.

Thanks for any input on this...

 

Well, how many miles does your car have??, I ask this because pending on high and even sometimes low mileage, it may be your motor mounts that are your culprit....

 

Thanks for the reply Searlec945.

The car has 122,000.

It cant be motor mounts because as I said she falls on her face when I accelerate slightly. (I can actually see the rpms drop momentarily) Usually as she shifts but always when throttle is barely cracked open and only when cold or not at operating temperature.

 

ANyone have any input on what this could be?

 

slight misfire... vacumn leak? put a scanner on it and check the live data on it, that should be helpful to find out wat the problem is

 

you got a scanner handy I can borrow? hehe

 

I realize this is 2 years old now, but if you're still around did you ever figure out what was going on with the cold idle/stumble on acceleration while the engine is cold problem? I am currently having the same issue. The car has been to the lexus dealership where they replaced both engine mounts and cleaned the TB. These changes have had zero effect on the problem. I have a 2004 GS430 with 103k miles. Please help!!

 

I got the same prob on my 01' GS430. No check engine light has ever come on... but I've decided it's a bad MAF and just ordered mine from Sewell yesterday. I was debating whether it was the APP or the MAF sensor, because it only ever hesitates when cruising, not accelerating. But finally yesterday, it did it while idling in park, so I can safely assume it aint the APP. I'll report back next week after the new MAF goes in. But I'm like 90% sure that's the problem.

 

My new MAF should be here next week. I cleaned the TB this morning though and car runs 100% fine. Oh well, good maint item to get fixed anyway.

 

Thanks for the info JiBBeL, it'll be interesting to see how your car performs with a new MAF. I have been suspicious of that for some time now. The other thing I’m suspicious of is if the engine is misfiring when it’s cold. Like you, I have no check engine light perhaps because I only experience this issue when the engine is cold. I’ll be looking forward to your update. Just out of curiosity, what does a MAF sensor cost? Thanks again

 

JiBBeL, do you have any update since you replaced the MAF?