OK, to make a long story short I will keep it quick.

I had to change the motor in my 2003 Infiniti G35 coupe, so I replaced it with the same year motor with about 60k miles.

After I get the car back, there are 2 big issues. The first is that there is somewhat of a hesitation or a misfire. The second is a oil leak coming from the rear main seal that the mechanic changed, this is however the least of my worries right now. I need to get the hesitation and the what I think is a misfire or fuel problem fixed ASAP so I can sell the vehicle.The mechanic tries to tell me that it is because of the car sat for about 6 months, and I needed to put some fuel in it and that would take care of the issue. Needless to say, 400 miles later and a lot of gas money the car is still not running correctly.

So I take the car up to AutoZone to get the codes scanned because the engine light is on. The code comes up as a 300, which I believe is a multiple misfire. I took the car back to the ripoff mechanic who persists to tell me that the problem is fuel. I keep pushing him to look into the issue since he just put the motor in 5 days prior, he tells me in order for him to check on the issues, it is going to cost $120 per hour for them to start digging in and trying to find the issue.

So I continue to drive the car and run more gas through it, here I am another week later and the issue is still here. Also, the check engine light is not staying on completely, it will blink sometimes, and other times it will stay on for about 5 minutes then shut off.

So this past weekend, my father and I took the car to discount and has the codes checked again and it came back as:

1)300 (Multiple Misfire)

2)P0021 (Intake (a) Camshaft Position Timing - Over Advanced (Bank 2)

So, the guy at discount tells me this is telling me it could be a few different things and blah blah blah. Well my dad and I bought a new Cam Shaft sensor for the passenger side of the vehicle because there is 1 on each cam. We did this and I drove the car around for about 10 minutes, and the problem was still occurring. So I took the car apart and started to dig a little deeper.

I went ahead and took all the coils out, and changed all the spark plugs with brand new Bosch plugs, put the coils back on, and replaced the other cam shaft sensor (driver side) with the one from my old motor that I know works fine. The car still seems to have a problem Idling, and when I accelerate, it wants to hesitate when I barely give it gas. It seems to run great when I floor the car or really put the petal down. So at this point, im almost about to take it in to Infiniti to have it looked at. Only problem is, after spending $1400 on the motor, and another $2000 for this crooked mechanic to put it in, money is tight. Yes you read right, I spent $2000 just to have the motor installed. My original quote for EVERYTHING was $1400, when he got finished with the work, my bill was $2000. No, I did not get a call letting me know the bill would be more than what I approved either. So I went ahead and paid the bill, and have it being charged back by my credit card company for the difference so him and I can have a small claim trip to find out what went wrong with his billing.

So needless to say I am really baffled. I am wondering if it could be a coil? If it could be a fuel rail or injector issue? I also just read that once these sensors are put in, I may need to reset something? I am not a mechanic but my dad knows quite a bit about cars so working on getting this part fixed isn't that big of a deal, just kinda would like to know what someone with Infiniti experience may think.

Has anyone seen this issue, or had an experience with something like this?

Thanks so much in advance guys, any help would be greatly appreciated.

Also, the original motor had 135K miles on it, and had to be changed because the rod bearing on it went out. I believe the rod bearing went out because the car somehow got an oil leak out of nowhere and I didn't know it till it started making noise one time, and at that point I think I had already done some damage. Don't ask me where the oil was going.... The car did not have a visible oil leak, there was no smoke coming off the car, and I tried to change the PCV valve or whatever it called. The car was still leaking about a quart every 2-3 days.... May have been leaking only when I drove I have no clue. Then one day the car basically started making a god awful noise, and in order to sell it I was forced to put a new motor in it. Now, I have a car that I paid a lot of money to have a motor put in, that I still cannot sell.

Thanks in advance,
Matthew Curry

PS- looking forward to all the help I can get.....Thanks.

 

Your old motor likely wasn't leaking oil, it was burning it. The rings on the VQ35 can be weak and the motor can start consuming oil. If you don't keep the oil level in the normal range, the issue can get progressively worse. The oil consumption problem really seems to affect the Revup motors (05-07 6MTs only), but the auto 03-07 VQ35DE 5ATs aren't out of the question, but a bit rare.

Your problem could be many things. Be prepared to start searching this site using some of the key words I list below:

1) Check for a vacuum leak. Warm engine vacuum should be a rock steady 18 to 20hg at idle. If it's bouncing, not steady, or low, you've got a vacuum leak. Check all vacuum hoses and remove, disassemble, and reinstall the intake tract from the throttle body forward. The smallest leak past the MAF sensor can cause all sorts of problems. You can pull vacuum from the nipple on the front passenger side of the intake manifold.

2) Verify that the coils plugs are attached to the correct coils. Yes, some people can cross the plug connecters. The car will run pretty bably. This probably isn't your issue but it's worth a look. A bad coil pack could cause the driveability issue you're experiencing, but the OEM coil packs are pretty sound. If you have the old motor, swap in the old coil packs.

3) If your warm idle isn't a rock steady indicated 600 to 700rpms, you've got an idle issue. Do the throttle body and accelerator pedal reset. This is a must if the throttle body harness was disconnected, especially if the battery was still connected when the plug was removed. The reset is a calibration procedure so the ECU knows the position of the TB plate and accelerator relationship.

4) Find the crank position sensor and make sure it isn't damaged or dirty.

5) Remove the MAF sensor and clean with electronics cleaner.

6) Trash the Bosch plugs. German plugs don't work well in Asian cars. Trust me on this. Replace with the correct heat range NGKs. Get copper $4 NGKs if you don't mind replacing them every 30K to 40K miles.

7) If all else fails, take it to Infiniti and type out exactly what's happening and what's been replaced. Your tech will greatly appreciate it.

 

This guy had a vacuum leak

https://g35driver.com/forums/g35-sed...ease-help.html




How to reset your ECU and perform the Throttle Pedal Release and Idle Air Volume Learning procedures on an Infiniti G35

Before attempting any of the following procedures, it is advisable that you read through the instructions thoroughly and familiarize yourself with them.

A stop watch or an analog clock with a second’s needle will be useful.

**a quick reset can be accomplished by disconnecting the negative battery terminal, and depressing the brake a few times.

ECU Resetting Procedures

Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON.
Operations Procedures
1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 second.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.
If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

Accelerator Pedal Release Position Learning Operation Procedure

1. Make sure that the accelerator pedal is fully released.
2. Turn ignition switch “ON” and wait at least 2 seconds.
3. Turn ignition switch “OFF” wait at least 10 seconds.
4. Turn ignition switch “ON” and wait at least 2 seconds.
5. Turn ignition switch “OFF” wait at least 10 seconds.

Throttle Valve Closed Position Learning Operation Procedures

1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch to “ON”.
3. Turn ignition switch to “OFF” wait at least 10 seconds.
Make sure that the throttle valve moves during above 10 seconds by confirming the operating sound.


Idle Air Volume Learning (Throttle Position Learning)

It is better to count the time accurately with a clock.

1. Perform “Accelerator Pedal Released Position Learning”.
2. Perform “Throttle Valve Closed Position Learning”.
3. Start engine and warm it up to normal operating temperature.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Confirm that the accelerator pedal is fully released, then turn ignition switch “ON” and wait 3 seconds.
6. Repeat the following (steps 7a, 7b) procedures quickly five times within 5 seconds.
7a. Fully depress the accelerator pedal (HARD)
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the Check Engine Light (CEL) stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the CEL is ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure the idle speed and ignition timing are within the specifications.

( this is from nicoclub.com)

 

Has the motor been tested for compression?

You should definitely do a reset on the TB, idle air learn, etc but I don't think this is yoru problem unfortunately. Start with swapping both OEM cam phase position sensors from the old motor into the new motor. Some people have had issues with aftermarket sensors from places like Checker, Autozone, etc.

If the coil packs were improperly installed your car would sound like it was cammed out and would run HORRIBLE. I very highly doubt this is your problem.

Its not the crank sensor as any inconsistancies would throw a P0335 code

Check the oil level. I've seen the P0021 come on from low oil before.

Is the wiring harness the same one you were using previously? Some of the OBDII readers have the ability to give you the feedback of the injectors. The dealer has CONSULT II which allows you to see so many different diagnostic values its amazing.