Engine/transmission Problem?

[Hckplyr]

I got an 01' IS about a month and a half ago. I have the 5 speed E-shift transmission on it. My problem is that when I want to open up the throttle at about 4000 rpm the engine revs but I get no acceleration which doesnt make sense to me at all. Is this a common problem or what?

[smooth1]

HHhmmm, depends on what you mean by no accelearation. The IS 300 produces most of it's torque down low. That's why it moves off the line as quickly as it does with little trouble. The issue is that there isn't much left once you get to the top of the rev range. So my question back to you is that are you saying there is a mechanical problem with the car, or that there isn't anything left for additional power higher in the rev range?

[Hckplyr]

Yea there is alot of low end torque but when I am punchin it the engine sounds like it is overrevving and the car bogs down. This may just be because I have a twin turbo 300ZX that has a lot of high end torque and Im not used to a NA vehicle. You maybe right that it lacks power and torque in the high end but why would that be?

also what can I do to remedy this feeling of moving forward in the seat of my car when it hits 4000rpm?

[bartkat]

Yea there is alot of low end torque but when I am punchin it the engine sounds like it is overrevving and the car bogs down. This may just be because I have a twin turbo 300ZX that has a lot of high end torque and Im not used to a NA vehicle. You maybe right that it lacks power and torque in the high end but why would that be?

also what can I do to remedy this feeling of moving forward in the seat of my car when it hits 4000rpm?

That doesn't sound normal. Is this happening wile accelerating on the highway or from a dead stop? Can you explain a little more thoroughly?

We know two things. The 1-2 shift on some IS is sluggish. If you are making a standing start, traction control will kick in if you spin a wheel and that will seem like a serious bog.

Otherwise what you're saying doesn't sound like a common problem.

[smooth1]

Yea there is alot of low end torque but when I am punchin it the engine sounds like it is overrevving and the car bogs down. This may just be because I have a twin turbo 300ZX that has a lot of high end torque and Im not used to a NA vehicle. You maybe right that it lacks power and torque in the high end but why would that be?

also what can I do to remedy this feeling of moving forward in the seat of my car when it hits 4000rpm?

You say youv'e had the car a month? And you said it was an 01'?

How many miles are on the car and when was the car last serviced?

If you "feel" there is a problem in the upper RPM range, then I would start with some of the "inexpensive" and easy fixes first, then move up from there. For example have you checked the air filter? And also check the rest of the intake and make sure there are no air blockages. Lack of air intake will effect the upper rpm range more than the lower as more air is required. If they have used an after market air filter that requires oiling, look in the intake after the filter and see if the oil has coated the inside of the intake. Usually it will effect the idle speed also, but not allways. Also, I have found this trick to be especially true for these cars as they get older. You might want to check the throttle cable connection on the throttle body for "extra play." See how much slack there is in the cable. there should be no more than a 1/4 inch of play there. Any more than that and when you're pressing the gas pedal your not really fully opening the throttle then. You'll see there are tensioners for adjusting the cable. But I have found where even those don't give enouph adjustment. If that's the case then you'll have to shorten the cable.

Also you may have a blockage in the catalytic converters, or somewhere along the exhaust.

If you find nothing there, then what I like doing, I don't normally recommend this to others, but over the years I have found it to be helpful to me in forming a complete picture of the car I have, and it only costs between 50-75 bucks. But go and get the car dyno'd. Make sure it has an exhaust sniffer and gives rear wheel horse power and not just flywheel. You should get 3 pulls. This will tell you if your running to rich, or to lean, how much hp. and torque your really making and where your peaking in the rev's. After you have that in your hand you will know exactly what needs to be done to get all you can out of that motor.

[DArustik]

Smooth 1 usually has ALL the answers ;). Especially about the IS'

[Hckplyr]

Its an 01' with 70000 miles and it was serviced and inpected by a lexus dealer before I bought it. This problem does occur when I want to gun it from a stand still. I get great accel of the line but the transmission seems to shift late. I use the manual shifter with the ECT power toggled on and I still get this effect with no power in the high end.

would you guys suggest I replace the ugly air intake with a new K&N or other after market intake or just turbo charge it. Problem with that is I am still in college and I dont have a whole lot of money once I get my tuiton payed each semester.

Also, is it possible that the E-shift transmission itself that limits the output to the wheels?

[smooth1]

okay, we have to get on the same plane here. When you say "shift late", at what rpm is it shifting from 1-2-3-4-5? Is it bumping the rev limiter?

College huh? better save all your money then. No power mods for you until graduation and you get a real job! Maybe mom and dad put a governor on your IS 300? :P

Seriously, here's a "back yard" dyno run test for ya. Do you have a video cam corder?

While your at a dead stop, put the camera on and aim it the speedometer. Then drive it like you just jumped in and stole it. Later when you get home play the tape back and use a stop watch. Tell me your times after that and we'll see if there is a problem or if your just power hungry. :)

[Hckplyr]

I actually did some more research on other sites and found that this happens to other IS E-shifts. Also the problem has only occured between 2nd and 3rd and only from a dead stop and before the engine gets to operating temp. btw mom and dad wouldnt know how to install a governor on my vehicle. Thanks for all the advice. Ill let you know if I have any more probs. Seeing that Im paying 8000 dollars in a couple weeks I cant do anything about it anyway.