Hello all,
I'm new to the forum but have used it a few times as a non-member but I have not been able to figure this one out so I am hoping some of you could help.
I have a 2001 es300 with 188K that started acting funny a few weeks ago.

It started out as a slight hesitation when I stepped on the gas from a stand still. It usually occurred in the middle of 1st and 2nd gear. I took it to a local shop and they replaced a few spark plug wires and all 6 plugs, but to no avail. Since, it has evolved. I drive about 40 miles to work each day (all Highway), and about 1/2 way through the trip, when cruising between 65-80 mph, the car will feel like it downshifts (but no change in RPM) and it lurches forward cause it slows down. If I hold the gas pedal right there, it feels like I cant accelerate. If I step on the gas it will sort of kick out of it and accelerate normally until I remain a certain speed for a while, then it will do it again. About 20 miles into my trip, I hit bad traffic everyday. When I get to that point and I am just idling, the RPM will be at a normal 750 or so, but the engine will shake quite aggressively, and the Check Engine light will start to blink (probably because it is already on cause of my evap system, but that shouldnt cause this, Right?) As soon as I step on the gas, the rumbling will stop, light stops blinking, and it will drive normal until I stop again. I immediately thought it was the TPS so I bought one and swapped it out, but it eventually started doing the same stuff again.
This morning when I was waiting at a light to turn left, the idle speed was surging to about 1500.
From what I read, it is likely the ICV or possibly the MAF. I really feel that this is an air related problem, but I am no mechanic. Could anyone help me out with this one. I need to try and fix this myself as I dont want to put more money into this car as I would like to get a new one in the summer.

 

Almost forgot,
I have ran a diagnostic and the only code it is throwing is for the evap system.

 

Try cleaning the ICV, just did on my buddies RX, it was amazing, smoothed her right out

 

Correct me if I'm wrong but the IACV is on the right hand, underside of the throttle body correct. I'm gonna try cleaning it tonight.

 

Yes,, It is best to remove it to thoroughly clean it, if you can keep from damaging the seal that is.

 

throttle body need cleaning??

 

ok, so I cleaned the MAF and the IACV but did not take the IACV off. (Draco, I didnt see your post till afterwards, sorry) I'm a bit of a newb when it comes to working on my own car so I have some questions that im hoping one of you could answer. I have read in other threads that the spindle that is inside the IACV should spin freely for about a 1/2 turn if it is clean. Is this correct? After I cleaned it, the spindle was spinning freely, but for only a half turn or so in each direction. Also, when you manually spin that, the butterfly inside the throttle body shouldn't move correct? (cause mine was not.) I appreciate any help someone can give me on this.

 

Yes, basically it isolates (opens and closes) in the IACV. If you take if off you will see that is need to be cleaned again, Sorry to say.