I30 stuttering when cold

[MattB]

When I let my '01 I30 (78K) sit overnight and then go to drive to work, it sometimes behaves strangely. When I start driving through the parking lot of my apartment building (obviously slowly) the car does something that I can only describe as stuttering...it's a mild shudder but it doesn't feel like the car is about to stall. Once I get out onto the road it disappears completely. This only happens when the engine is cold and the car has sat over night. I know this is a little vague but any kind of direction to look in would be appreciated.

[maxnix]

First, you provide no maintenance history, so very tough for us to guess.

Secondly, I think you need to familiarize yourself with the concept of operating temperature. Running faults when cold are not really faults, but indications of deferred maintenance.

[MattB]

I would say that I maintain this car quite well. Fluids are flushed on schedule, oil is changed with Mobil 1 full synthetic every 5K, filters are changed every year or 12K, and the maintenance history shows this car had been well cared for before I purchased it. Maybe I missed something, but I'm generally pretty good about taking care of this car.

[qship96]

Check, check, and recheck the transmission fluid level and condition{color,smell,turbidity} following the procedure EXACTLY as outlined in your owners manual

[MattB]

Why would the transmission fluid be an issue? There are no leaks and the system was flushed 10K miles ago. The problem also doesn't occur every day.

[qship96]

Did you check the trans. fluid level? You state you feel a "mild shudder" when engine/transmission is first operated for the day.....possible ATF is on the low side when cold, atf expands when warm, therefor problem disappears as transmission warms up.

Certainly wont cost one dime to rule out

[maxnix]

Or it could be overfilled and cavitating the ATF into foam.

Still, always check performance at operating temperature. Any top end fuel system, intake system miantenance performed? EGR and IAC valve? Plugs? Filters?

[MattB]

Or it could be overfilled and cavitating the ATF into foam.

Still, always check performance at operating temperature. Any top end fuel system, intake system miantenance performed? EGR and IAC valve? Plugs? Filters?

With 78K, I'd imagine I'm coming up on needing plugs. The filters are good, the air filter is less than 5K miles old and the fuel filter checked out as good at the last oil change less than 1K ago (I asked to have it checked and replaced if needed as preventive maintenance). A dirty IAC or EGR valve could be a possibility, especially given that the stutter disappears and doesn't come back as soon as I hit the gas. Maybe the car just needs a tuneup?

[qship96]

Exactly how does one "check" a sealed metal fuel filter, and determine it is still "good" ?????

Unlike the air filter element which can be visually examined, the fuel filter element is not visible unless you cut it open, and at that point no longer usable....best to just replace annually.Cost is $10 or so from online suppliers

[MattB]

Exactly how does one "check" a sealed metal fuel filter, and determine it is still "good" ?????

Unlike the air filter element which can be visually examined, the fuel filter element is not visible unless you cut it open, and at that point no longer usable....best to just replace annually.Cost is $10 or so from online suppliers

Why is the dealer telling me it isn't replaceable? Is the last dealer I took it to just stupid? I wouldn't be surprised really. I'll definately have it changed when its in at the new dealer I take it to down here in DC.

[maxnix]

Is it in the tank filter or external in line? In line should be replaced annually, or even more frequently in ethanol areas.

[MattB]

Is it in the tank filter or external in line? In line should be replaced annually, or even more frequently in ethanol areas.

The dealer said it's in the tank and not designed to be replaced, but I'm not entirely sure on the A33 design.

[Sentientbydesign]

A32 had 2 filters IIRC, the A33 and newer only have the in-tank filter that is designed to work for the life of the fuel pump.

I would check plugs AND wires. It's possibly an electrical issue that "fixes" itself when the car warms up.

[qship96]

90-96q owners manual also does not call for ANY replacement of the fuel filter for the life of the car....just says some lame "if driving in dusty or abnormally high/low temperature environment the filter may clog,if clogged replace it"- even though it is simple to get to under the hood.

[Sentientbydesign]

The A32 filter was in an annoying place. I ended up having to cut the hose to get the old one out.

I think they realized that there is not really a necessity for 2 fuel filter. Especially with the stringency that gas refineries have to deal with these days (this is speculation).

[maxnix]

90-96q owners manual also does not call for ANY replacement of the fuel filter for the life of the car.

I thought it was on the 30K maintenance check list?

[qship96]

I thought it was on the 30K maintenance check list?

NOPE!!

Transmission and rear differential fluid also has NO replacement interval {LIFETIME FILL] unless you are towing or using a rooftop carrier or driving on mud roads......what a joke!!!!! Guess those 18 quarts of Redline D4 ATF I swapped out 2 days ago was a waste of time according to Nissan!!!!

[MattB]

Problem solved. Culprit was a bad MAF sensor. New MAF sensor fixed the problem.

[maxnix]

Transmission and rear differential fluid also has NO replacement interval {LIFETIME FILL] ...

On the G50 we bought here, I asked the service writer if the differential fuid was changed at the 30K service.

He said, "No, we just inspect it and leave it if it soesn't look bad."

I said, "Well, isn't it too late if it does?"

What most people don't understand is fluids are not meant to be visibly degraded if you change them in time. Once they are visibly changed, serious degradation has set in.