top rmp 3000?

[SqueekyQ]

My 94 Q is acting up lately.

One day after I made a left turn I couldn't accelerate. It stays in one gear and lurches when I floor the gas paddle. It will shift if I press the gas slowly and gently. I though there is something wrong with the transmission.

After a while the problem went away for a couple of days. It shifts but the rpm will drop and die when I brake hard or put in neutral or park.

The next day, it won't die but it won't shift again. So I did something I should have done, I put it in park and floor the gas. The rpm goes up to 3000 and stops there, if I try again, it will go to around 4000 and stop. At the same time, the muffler is pass gas like all the crappy cars in the movies.

From my simple diagnose, it doesn't look like a transmission problem. It might be an air / gas related problem.

Car info

94 Q, 167000 miles. Humming gas pump.

4 years ago, replaced air meter ($700 at Infiniti dealer) because of rpm drops and engine dies.

3.5 years ago, same problem(rpm drops and engine dies) occurred, spray clean the EFI throttle body with one bottle of cleaner ($2)

Sometimes hard to start after sitting in the garage for days.

1.5 years ago, changed transmission fluid, drop pan.

Recently moved to Florida. Hot and humid and full of small animals

3 months ago: Clean EFI throttle body, replaced Air meter connector due to same problem I am having now . Also replaced belt tensioner.

2 weeks ago: Fuel injector cleaner, water remover in two seperate tank of gas.

[elwesso]

Do you have a check engine light???

The humming fuel pump could be a clue but I doubt its causing your problems... The first thing that came to my mind was the CAS. Whenever the CAS fails it goes into failsafe and will not allow the engine to go above 3-4k RPM...

[DAEDALUS]

At the same time, the muffler is pass gas like all the crappy cars in the movies.

Could you expand on that statement?

A transmission electrical problem could cause at least some of the symptoms, even just a loose connector. Jiggle all the connectors you can see under the hood and make sure they're all tight. If there's no check engine light, run the self-diagnostics on the transmission.

[SqueekyQ]

There is no check engine light.The fuel pump has been humming since I bought it 4 years ago.What’s a CAS?

When I floor the gas paddle, the muffler sounds like it is backfiring. And it is giving out some black smoke. It is doing that when it is in park. Can it still be caused by the transmission electrical system?

[SqueekyQ]

There is no check engine light.The fuel pump has been humming since I bought it 4 years ago.What’s a CAS?

When I floor the gas paddle, the muffler sounds like it is backfiring. And it is giving out some black smoke. It is doing that when it is in park. Can it still be caused by the transmission electrical system?

How to run a self diagnose on the transmission?

Thanks a bunch guys!

[Jesda]

I have these exact same symptoms when I start the Q after a hot soak (go for a long drive then park on a hot day, then come back, start it again).

I still dont know what causes it on my Q, but I'm currently suspecting the MAF or injectors. I know that when the connector pins on the MAF are very dirty or disconnected, the RPMs will be limited to 2000 or 3000 and shifting will be very rough or impossible unless you accelerate gently.

I wonder if the heat is causing some connector to come loose, or if the heat on the injector coils is causing a fuel delivery problem at startup.

I also replaced my MAF, but it was last year and with a used unit out of a 96 Q45 (I swapped connectors). Unlike your situation, my symptoms don't occur during normal driving -- it occurs only one minute after startup after a long drive on a hot day.

I'm giving my Q to my brother, so I told him to just live with it unless I can find a cheap fix.

[DAEDALUS]

When I floor the gas paddle, the muffler sounds like it is backfiring. And it is giving out some black smoke. It is doing that when it is in park. Can it still be caused by the transmission electrical system?

You're running way too rich. It could be a MAF problem, so get a Consult or at least a voltmeter reading off the MAF at idle. But if gas is pooling in the exhaust (backfiring) I would also do a leakdown test on the fuel rail to see if you have a leaking injector seal.

[maxnix]

The fuel pump has been humming since I bought it 4 years ago.

What’s a CAS?

Major red flag! Replace it before you have to replace the FPCM also.

Do you have a manual? If not, download it and all the TSB. Then read it.

CAS = Crank Angle Sensor

You need to spend some time learning how to search and reading the previous posts.
Modified by maxnix at 8:36 AM 7/27/2005