I have a 2004 G35 coupe that seems to lost a little pep when you step on the gas. It has about 70K miles on it. I bought it used about 2 years ago with 55K on it. I have done the regular oil change every 3K and changed the air filter.

Here is what I notice. When I step on the gas it seems to be a delay from when the car takes off, about a second or 2. And when it does it just dosen't seem to be up to par.

I called the dealer to see what kind of service plans they had. They had a 75K service plan where they change the oil and the filter and check a whole bunch of things. This was about $350. This seemed high because all they are doing is checking things out and then they will charge me to fix anything they find. It seems like an expensive oil change?? Should I get this service?

I was thinking about getting some high performace spark plugs and cables and having the timing belt checked out at a local place that has a good rep.

Any other suggestions?

D

Hmmmm...

Try something as basic as a compression test. That's what I would do at first.

Things to check/do/change since you didn't mention the items below being done, before the compression test, IMHO:

1) Bad gas?
2) Clogged fuel filter?
3) Old Plugs/Wires?
4) ATF/diff oil

You mention timing belt. If it's a belt, maybe a belt change is due? If it's a chain, then disregard.

our cars have a timing chain, no rubber belt. no need for fancy spark plug wires either since our cars have no coil.

They have 6 coils, one atop each spark plug. These coils are very very sensitive and often need replacement just after warranty expiration [but that throws a code or a series of codes].

Electronic throttle body problems?

What mods do you have? Clean the MAF sensor and run a vacuum test to make sure you don't have a tiny vacuum leak in the intact tract.

Like others mentioned try these things:

Clean the maf sensor
Clean the throttle body (mine was filthy @ 65k miles)
Change the spark plugs
Check for any air leaks starting from the air intake to the intake manifold

Is cleaning the TB a good idea based on how many threads arise as a result of people cleaning them?

There is a DIY Video on YouTube.

BTW: I notice your in Cheseapecke, come check out our local Hamton Roads tread here
https://g35driver.com/forums/northea...owners-38.html

Whats that video under?

And also try ECU resetting.

I used to have problem of losing trottle response and it was recovered right after ECU resetting

DO NOT clean the throttle body. It is in the Factory Service Manual - says do not clean.

You are not having issues related to this.

First place to start would be to change out your spark plugs. NGK Iridium IX or NGK Platinum. New air filter? Or clean air filter if you have an aftermarket filter.

Can anyone explain why its not a good idea to clean the throttle body ??

Newb here..

They are very sensitive. Nobody knows exactly what the sensitivity is to. It could be the throttle plate (butterfly) position that if moved will cause a problem. It could be the chemicals that are used in the TB cleaners. All I know is that its been a PITA since I cleaned mine. I've had 2 other TB's besides mine that haven't worked.

Besides, there is no reason to. Its not going to help anything. FSM specifically says not to clean.

The only time i would clean it is if your idle dropped do to TB failure....not common.

+1 exactly what I would do