Engine Stall and Limp mode problems, I NEED YOUR HELP!!

[sleedesigner]

Hello, my name is Sean and I live near Detroit Michigan. In my town there is barely any G or Z cars so it is really hard get help when I get any problem on the car. If you are in Michigan and know any shop who knows G35 well, please let me know. Also I don’t have much knowledge about car’s mechanism so please be mindful on my explanation.

I have 2003 G35 coupe 6sp and recently I am suffering a mysterious and stressful problem with my G from last 3 months. It’s been 4 years since I bought a used one and I took a good care of it ever since. It currently has 125,000 miles and I drove it from 80,000 miles.

Before I begin my story(very long), I would like to summarize the problems I currently have:
-Engine stalls on start up. I can keep it going by pressing a gas pedal, but the idle is unstable and can immediately get into a “Limp Mode” (with VDC,SLIP, Engine Service Soon Light on) with 1000rpm limit, 10 MPH speed limit

-Also I get 7 different OBD code when I scan

-Possible electrical problem but have a no ideas. No mechanics so far found out the exact problems. Replaced TB and MAF sensor did not work so far. Also I still get a MAF sensor code even after I replaced it.

To begin with, I want to mention my previous repair history which I think might affect to the current situation.

On last November, my car’s audio and climate control starts to disable. Sometimes it works, but sometimes the entire control is lost after few sec~min of vehicle start up. When controls are lost, I get a full blast of the air from the vent (although my climate system was off, it automatically starts) with the last preset temperature I had. But I still had audio sound and control from the steering wheel. Just no display and control from the center stack.

Other function was normal except the audio and climate control. Navi worked fine as well. I kept drove it.

On last December 27, after 100 miles of driving (I was in Canada), the car suddenly got into a limp mode when I was making a right turn. It was pretty cold day and I went for sking so the temperature was fair low (10 F or something) I had a climate and audio control alive on the center stack that day (some days it worked through entire driving, sometimes it just dead on the start-up). I stopped a car and turned it on again, the Limp mode was still engaged. I did it few times and finally the limp mode was gone, but the Engine service soon light came on and stayed.

Early January, I replaced the audio unit purchased from Infiniti dealership. It was installed by a local shop that specializes in Nissan and Infiniti (In Toronto, Canada) I also told them that I went to a limp mode once and they did OBD scan and told me the code is from the knock sensor. They just told me to drive more and see if it comes on again. They erased the code. They also noticed that I have a ticking sound from the engine and told me it might cause knock sensor to pop up the SES light.
In mid-January, One day the limp mode is on again after I exit from the highway and drive on the local road (About 30Mph). I pulled the car and started up again, the limp mode is gone and SES light is on again. Went to the local shop and pulled a scan code. They told me I have a numbers of code, just erased the code and did not do anything.

About a week later----------------------serious stuff begins
One day, I drove car for 30 miles and decided to change my air filter and put some addictive to my engine oil. I Went to Autozone and got a new 3” cone filter for my Injen Short Ram Intake. I changed filter and put an addictive. Car started up fine and I drove for another 30 miles on highway. After few hours, I started car and it went stall right away with the limp mode engaged. I tried to start up few times with pressing pedal, and it started but limp mode was on. I turned off and on but the limp mode is still on. The day was very cold (0 F) so I keep the car running about 30 min with the limp mode on. Suddenly some weird noise is heard so I went out, the car start to throw out coolant from the reservoir. Coolant temp was normal and there was no steam when I open the hood. It didn’t throw out a lot, but some coolants were spilled. I got scared and called a tow truck to my local shop that I went a week before.

They tried to start up the car normally. So cleaned throttle body and MAF sensor and so on, but did not solve the startup problem. ECU reset is tried but nothing happened (Limp mode still on) They said the fuel system is fine so they said I might have a bad TB or MAF. So I replaced to brand new OEM TB and nothing got better. So I replaced MAF Sensor, but still the same. The car is in a limp mode all the time so they told me they could not perform re learning stuff on TB and MAF sensor. The mechanic said he checked everything (wire,fuse,relay etc) he could possibly do. I also changed to new engine oil (Mobile 1 full synth extended performance 5W-30)

So I ended up with spending $700 for new TB and MAF sensor and the car stayed a whole week at the shop. Nothing got better so I towed it to the Infiniti dealership.

Dealership did a diagnostic and pulled a scan code. However, they told me that they need more time to look at the wires and stuff to find out the exact problem. They told me it’s a $600 to just find out the problem so I said no thanks. But I got OBD codes and mechanic’s opinion on the car’s situation. So here are my OBD codes:

P0550 Power Steering Pressure Sensor Circuit Malfunction
P0605 ECM Fault
P0052 Air Fuel Ratio Sensor 1 Heater Bank 2 Control Circuit High
P0327 Knock Sensor Circuit Low Input Bank 1
P0102 Mass or Volume Air Flow Circuit Low Input
P0113 Intake Air Temperature Sensor Circuit High
P0183 Fuel Tank Temperature Sensor Circuit High Input

Strange thing is that although I have a new TB and MAF sensor, the code is still up for MAF (P0102). Power steering is perfectly fine but there is a code for it. So I have no clue with this.

The dealer said I may need to replace ECM. Knock sensors, o2 sensor and fuel tank temp sensor.

Also they noticed for my ticking sound from the engine, said engine lifter noise is from the right side silicone, need to replace intake manifold gaskets, valve cover gaskets and lifter buckets. However I don’t think this is related to other problem.

Yesterday, I towed my car back from the dealership and tried to start up the car. It started without being on a limp mode (but still SES on) so I drove for 30 miles. Car drives normally, no loss of power or anything

Today I start up the car and it is on stall right away, tried again and pressed gas pedal to keep it alive, but the limp mode is on. So I turned off and on again and the limp mode is gone. Drove for 30 second and the limp mode came back, so I parked it and turned it off.

----------weird-------When I turn it on again, the speed and rpm needles were not moving at all but the car started. Background light was on, limp mode lights were gone, but the oil pressure warning light was on with it (WTF?) so I turned it off and on again, the needles were moving normally and the car started without being on a limp mode. I got scared so did not do anything else after this.

And here is my personal questions:
-Is there any possibility that my current situation is related to my previous audio unit problem? (circuit board thing which I replaced)
-A dealer wrote that my car’s battery is failed on the capacity test. Is that meaning my battery is done? And might cause this problem? It’s been 2 years since I replaced it. I don’t see any signs of short battery yet.
-Maybe bad ECM caused all the problems?

I don’t really know what to do now. The car is sitting on my house parking lot and I don’t know where to go for real diagnostic and professional repair. So I am desperately asking for any suggestion and possible cause. Thanks for reading such a long post and I am looking for any reply so please help me if you have any idea on my situation. I thank you in advance.
-Sean-

[telcoman]

Sorry to hear about your problem.

Your vehicle is now 10 years old and about to become 11 years when the 2014 Q50 hits the showroom floor in a few months.

You've already spent $$$$ and I have strong doubts if anyone other than a dealer is going to have the experience and expertise to repair your vehicle without following the factory flow charts replacing parts that is going to cost you not only money but time.

My advice is to start shopping for another vehicle. Suppose you spent another $2k on repairs and drove it home. And on the way home someone drove into you and your vehicle was now totaled.
The insurance company is not going to care that you just spent $$$.

My $.02 is get rid of it.

Telcoman

[sleedesigner]

Sorry to hear about your problem.

Your vehicle is now 10 years old and about to become 11 years when the 2014 Q50 hits the showroom floor in a few months.

You've already spent $$$$ and I have strong doubts if anyone other than a dealer is going to have the experience and expertise to repair your vehicle without following the factory flow charts replacing parts that is going to cost you not only money but time.

My advice is to start shopping for another vehicle. Suppose you spent another $2k on repairs and drove it home. And on the way home someone drove into you and your vehicle was now totaled.
The insurance company is not going to care that you just spent $$$.

My $.02 is get rid of it.

Telcoman

Yeah Q50 is coming !! and in fact I only need to drive my G for next few months max because I might leave U.S soon. However I need a car for next few months and getting another car is a bit risky - buying cheap used car is always painful. And dealer said they would take my car for $1,500 which is nonsense and I don't have money to get a new car anyways. I hope somebody just hit my car at the parking lot overnight so I can total my car with a insurance coverage. I just want my car to be running without blowing my engine up or something...

[audtatious]

maybe I missed it but have you been digging through the FSM to follow the diagnostics for each code you are showing?

http://www.nicoclub.com/FSM/G35

[kmckis1029]

wow... thats a lot...

i agree with telcoman...

get a new car when you come back to the USA sounds like you deserve it lol

[tollboothwilley]

Sounds to me like you have an ECM issue - I VERY HIGHLY doubt that you have all of those things wrong with the vehicle. Have you unplugged the battery overnight (8+ hours) to let the ECM(ecu) fully drain of electricity and reset? If not, try this. It will erase all codes and let the car function normally for a short while as it runs diagnostics.

If, in the end, you keep getting issues, there are a few things to look at.

TB has been replaced, MAF has been replaced...you could have vacuum leak, or you could have fuel pressure issues. Fuel pressure at idle should read 51-55 psi if i remember correctly. Test that to make sure its accurate. It can throw a bunch of random stuff when the fuel is off. Start with those few things and report back.

[mistib]

Did you Figure out what was the problem? My M45 had been doing the same and no one can figure out why. Runs fine for a while then Slip, DVC and Check Engine comes on and No matter how hard I push the gas it will not go. It might die then it might not. I have been pulling in to traffic or on the interstate and it will NOT go. If I am lucky it will kick in and go but most of the time i have to turn off the car and start back. I had the codes ran a couple of times but only thing it says it is losing power to the engine.. I know that. The Dealer wants to keep it for few days and try to trace down problem at $135 an hour!

[sleedesigner]

I ended up with replacing my ECM unit. The new part was about 1500 and required dealership to re-program it. I got the used one for about $ 400 and ended up with abut $750 with the reprogramming. However, After that I had my car on Limp mode twice later again!! and one was happened in the highway so it was really dangerous. I completely lost my trust in this car. I am selling my car now and I wont never buy Infiniti/Nissan vehicles again especially 2000s models. And also Don't go to the dealership. they might charge you 1000+ dollars for diagnostics only. I don't want to know the price for the repair. I rather get a new engine and get a swap or something. This car is sucks. I really hate the limp mode. Hope your problem is not serious as mine.

[joe603]

Limp mode saves the car from expensive damage. Any used car comes with some kind of risk for things to go wrong...who knows how the previous owner treated it. Not sure why you didn't go with an aftermarket ECM...