IS250mr2

updating... My gf returned the 250. She said " it doesn't feel like it used to. And I hate the shaking." The lexus was never the same after the rebuild. It was nice being in the lexus club.good bye guys. Thanks for all the help. Well probably return when they have a real solution.

drewster12

iTrader: (4)

So this is what I've been doing. I have an 06 and at 120,000 miles, my car began to have a rough idle. Upon a spark plug and oil change, the symptom didn't go away. I poured a bottle of Seafoam into the gas tank, filled it up and ran it to empty and the car felt really good. 2500 miles later, I opted to give it a second treatment and so far even better. I'm going to put one more bottle right before the next oil change. In the future, I will treat it once before an oil change to maintain it.

chikoo

Is the intake valve open when gas is bieng injected into the combustion chamber?

topspeed55

Of course it is, how else can there be ignition without air. If anything, the intake valves always open and close as long as the engine is running, they will open with or without fuel. It can open less or more under load. Fuel can be cut out completely though, like when you let off the gas and slowing down in gear.

topspeed55

Sounds like you had dirty clogged injectors. According to the information on here, being a solely DI engine, seafoam in the gas tank does very little to clean the intake valves. That method only really cleans the injectors. Instead, if you sucked the seafoam into the intake manifold, that should hit the intake valves and clean them.

chikoo

That might explain why BG-44K seems to be working for me in cleaning the carbon off of the piston heads as well as the intake valves.

mrraider

I noticed the rough idle recently. It's only intermittent, an doesn't happen every day. There was no CEL. I used an OBDII reader with torque app on my phone to try and pull any codes, and there were none.

What's the chance i can get the dealer to do the rebuild? Should I wait for worse symptoms? I still have 18 months left on the powertrain warranty.

Toymota

Yes, the Toyota information says that most of the time, the gas is injected during the intake stroke. However it also says when the engine is cold, gas is injected at the end of the compression stroke, for emissions purposes.

The 4GR-FSE engine does not include variable valve duration or lift; only timing (phasing).

chikoo

I should rephrase and ask this:

Does the intake valve open into the combustion chamber? ie. is it pushed in or pulled up to open?
If it is being pushed in and the gas is injected at the same time, it might explain why the BG-44K has had some positive effects. If it is not the case, then the positive effects could have been due to cleaning of the piston heads.
Either ways, the slow idle is no longer happening.

Furashu

I am considering purchasing an IS250, but this has worried me a bit.
Most of the used 250's from private dealers are 2006-2008 and more are out of warranty.

When I test drive any 250, should i take it to the freeway and then see if it has these issues?

Thank you.

J3ffrey

I wouldn't buy a 250 at this point. There are way too many hidden problems with this car.

Out of every single car I've owned, this is the only one who needed a short block at 67,000 miles.

My dealer has been great, and I will be going to them for my next car, but I'd avoid a 250 if I had to do it again. I lucked out that it stalled at a red light and was under the 70k..

Furashu

I know the 350 doesnt have this issue, but wouldnt other "hidden" 250 issues be the same within a 350?

shadowman

iTrader: (2)

Freeways aren't the issue unless you were stuck in a stop and go traffic.

After driving 40+MPH and coming to a stop, the car's RPM will drop below 500RPM and cause the car to sputter. If the carbon issue is really bad, the car will stall and give a CEL

You also want to keep the A/C on as well since it puts load on the engine, it usually cause my car to get that nasty feeling at stop lights.

Furashu

I drive in about 20 minutes of bumper to bumper traffic every morning, so this will be a big concern for me.....

Yeah sorry I meant, i will drive on the freeway then exit and see how the car behaves at the stop light right off the freeway.

shadowman

iTrader: (2)

^^^ Make sure A/C is on.... or at least have the fan on.

I am able to get the car to sputter with the above. Still waiting for the CEL so I can get it worked on...