RPMs drop when braking/pressing the clutch
 

So guys, the only problem I have left with my car is when I am braking/pressing the clutch the RPMs will drop around 200-300ish and then sometimes recover, or sometimes stall. I never have a problem starting it right back up, and I have no codes. After doing a ton of searching, I have came to the conclusion that a LOT of people have this problem, and no one has (verifiably) fixed it.


I am looking for some people who have this problem, a copy of the FSM, and the know-how to use it. I scrolled through the symptom matrix in the manual on pgs EC-83 through EC-85 and there are a lot of good possibilities. There is just not enough time in the day for one man to check all of the possibilities. I'd like to start an ongoing list of things people have checked, things that have helped, and hopefully find a permanent solution.


One thing that I know it is NOT: the MAF. I have tested it using the method in the FSM, and I have replaced it regardless of the correct readings. It did not fix it. I have also tested my TPS according to the manual with a multimeter and it tested in spec.


Does anyone want to take this journey with me? If we create an ongoing list of things from the manual, and test all components per the manual, and report all evidence of the tests here in one location, we will undoubtedly find the solution. Every time someone tests a component using the method in the FSM and reports actual values they got from the test I will edit this post and add the results to the list.

Horrible thread title...not a good way to ask for help. I revised it.

Chad - What year model is your Max? It helps if you have some information about your car in your profile or signature.

You're right, I should put something about my max in my signature. But I think it's safe to assume I have the same engine as most people in the 4th gen forum. VQ30DE. Non-cali. Are the any differences between the years?

I have a '97.

The 99 models have an electric EGR. A few months ago, my 99 model engine had difficulty idling and starting that I traced to clogged/cooked cats. I removed the O2 sensors (while leaving them plugged into the electrical connections) so the engine could properly breath and took it for a drive. That made a good improvement. So I replaced the cats with a Y-pipe and a Magnaflow high-flow cat.

Then I had a handful of hard to pin-point issues that would happen sometimes -- but not always that were corrected with a new EGR. I noticed the RPM would drop extremely fast when I would press in the clutch. Sometimes the car was hard to start and it didn't seem to idle properly on occasion. One morning I got a CEL code for the EGR. I quickly replaced the electric EGR that day and it made a huge difference. I never thought an EGR would make that much difference but it did..

Do you know if your EGR valve and pipe are clean?

I remember getting an EGR code on my 95 Maxima 5MT with a vacuum controlled unit that is unlike the 99 model's electric unit. When I replaced the EGR on the 95 model, the engine also performed better and shifted smoother. I don't want to see you through parts at your car. All I can tell you is a failing EGR sure wreaked a lot of havoc with the 99 model 5MT and some years earlier with my 95 5MT.

When you say you replaced the "EGR" are you talking about the tube or valve? I have cleaned everything. Throttle body, IACV, EGR tube, MAF, and some miscellaneous connectors throughout. The EGR was actually relatively clean when I took it off. It had soot on the walls, but a pipe cleaner went through without any resistance. The EGR valve is actually a good suggestion. But, I have already tested that. I don't remember if I checked the entire EGR system because it gets a little hard to understand in the manual, but I checked the solenoid valve circuit with a multimeter and it tested in spec.

The actual EGR valve in the picture below. The 99 model uses a Hitachi electric motor in the picture instead of a vacuum value. I had cleaned up the IACV, EGR system, and a few weeks earlier. I had accepted the way it was running which was much better than when it had broken injector pintle caps that were causing a misfire and I liked improvements brought by the y-pipe and high-flow cat. It performed great on the highway. But members on here will tell you I was still searching for a reason for the start idle issues that kept it from really running like a new car - especially after all the time and money I had invested in it..

So it finally threw an EGR code one Sunday morning that tipped me off that it might be having a problem. So I picked up a new one later that day that took care of all the hard to pinpoint issues.

I don't know if the vacuum operated EGR valve will have the same impact as the electric, but it sure made a noticeable improvement with the 99's low RPM performance.

Attachment 21819

Is it possible to put the '99 EGR valve on a '97?

I would not make that modification.. I like the simplicity of the earlier 4th gen models.

IN your situation I would replace the FPR if its never been done, and also clean the ground connections on your car.

I have already done both.

OK how about the crank sensor, the one located near the flywheel? CS_AR point out how it can get full of metal shavings. Being a magnetic device, those metal shavings could make the ECU readings of crank position somewhat sketchy. Fixing it involves cleaning the sensor, no need to replace it, unless you want to.

This could relate to your situation because your circumstance involves a slight drop in rpms which the ECU may not be detecting properly:gotme:

Also, fact is, it's an old car. The FSM tests are run on a newish vehicle, so they are more definitive. Ground issues? Unlikely. Tired O2s? Nope. They're either good or they're bad, not tired.

Haha, I have actually change that too with a brand new one from AutoZone. I had a misfire problem and I ended up changing soooo many things before realizing the remanufactured injectors I got were not working properly. That crank sensor actually tested out of spec and I was so happy when it did because I thought my problem was solved. Oh how disappointed I was.


I'm telling you, I have changed or tested almost everything. I know for a fact though that I have a leak around the top of my radiator, but the car has never ran hot so I haven't bothered to fix it. Would a coolant pressure leak cause this? Is it possible that my car is not running hot, but running hotter than usual causing this problem? The temperature gauge always starts at the bottom, slowly rises to just below the middle and stays there. It has never gone above a little less than half way.

Another thought, I got this car for Christmas of 2012 and it had a knock sensor code. I replaced the knock sensor with a cheap one from eBay. Is it possible that this sensor is basically just good enough to prevent throwing a code?


I find this article quite interesting:
http://forums.maxima.org/4th-generat...operation.html

Chad - Where are you located? You might be near one of our members who would be willing to take a look to help you get your Max fully operational.

Columbus Georgia for about the next 3 weeks, then I am moving to the Atlanta area. I will post a video later today to show exactly what is happening. It seems the RPMs have been less cooperative since it has been raining a lot. It seems to drop and then recover, but only get up to about 500 and it will then stay there.

Atlanta has lots of Maxima and Infiniti expertise for sure. Also, a ton of used a parts cars to pick from. Q45 people call the area Q-topia..

Just looking at CL the Maxima and Infiniti selection is loaded.

Check out this Atlanta I30 5MT as example.

http://atlanta.craigslist.org/nat/cto/4571645007.html

I've known of people in the Infiniti world who drive from places like Baltimore MD and Washington D.C. to get their car serviced at T3 in Atlanta.

http://www.t3atlanta.com/

I also see we have a Maxima.org group in the Atlanta area.