Altima hesistation off idle, revisited again!

Thanks, I have actually noticed that there is a fair amount of rust on the cover of the ECM, I assumed it was just from humidity / salt from winter boots, but maybe I'll pull it out and get a closer look!

Reply to
JM
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One thing you could try as it's easy, is to adjust the TPS outside of the normal tolerances, I've noticed smoother low speed pickup doing this on a very high mileage 94 SR20, with no problems noted. I went about 0.1v lower than spec.

Reply to
SteveB

I actually wanted to try this, but the TPS screws are quite hard to get at, and don't want to turn. I'm afraid I'll snap one off or destroy the head so I haven't worked too hard at it, especially since it seems to be set properly and shows smooth operation on my meter.

Reply to
JM

This may just be your hypersensitivity to any and all test measurements, i.e. it may be a normal amount of needle movement. FWIW, it is more normal for a vac gauge reading of manifold vacuum to flutter at idle than above idle due to the dynamic airflow differences and pulse frequency of higher RPM operation.

If it does happen to be excessive, you could have a large amount of carbon buildup on the back side of the intake valves. This could cause valves to intermittantly stick open depending on how soft or hard the carbon lumps were (varies with amount of fuel soak and temperature)

Some shops have a fairly effective fuel service machine for cleaning injectors and intake components. The popular make is called MotorVac, and any shop will know what you mean if you ask if they have one. If you don't come up with anything else, and you insist on attempting all diagnosis yourself, you may want to keep this service in mind.

Toyota MDT in MO

P.S. my feeling on the MotorVac thing is that it *does* what it is supposed to do, but many mechanics use it as a diagnostic machine -- IOW, "lets charge you one labor hour plus chemicals and see if this makes a difference" on every drivability complaint, then when it doesn't affect a change, real diagnosis becomes necessary. This process is a profitable one for shops who employ "parts changers" and it pays for the expensive machine in a hurry. Just know that a MotorVac service can either be *really* necessary -or- a waste of money.

Reply to
Comboverfish

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