2009 FX35 Limp Mode? RPM's rev, but wont go over 35ish....

[kmikebennett]

Can someone please help? 2009 FX35 seems like it is in limp mode. It will not go over 35-40. RPM's are revving. I have replaced a misfiring coil and replaced spark plugs. I am attaching my diagnosis. Thank you!!

[VStar650CL]

None of those codes will make your car go limpy. There are only four things on most Nissan products that the ECM can't monitor directly and has to trust:
MAF: The MAF is always a prime suspect, even a piece of lint can send the readings off into Wally World. Try cleaning it.
Fuel Pressure: Symptoms are usually "hitting a wall" at a certain RPM or when punching the throttle. Nissan fuel pumps are all monolithic, so if the pressure is down, replace the assembly.
Exhaust: Check with a vacuum gauge, it should read 18~20" at idle, drop and then recover when the RPM's are raised. If it instead drops way off and stays low when you raise the RPM's, there's a blockage (probably a melted cat).
Crank and Cam Sensors: The ECM's are very good at detecting "flatlined" sensors but terrible at detecting ones that work but aren't working well. There aren't many good checks for that. It's a replace-and-try scenario, so check the other possibilities first.

[kmikebennett]

Thank you... Working on cleaning or replacing MAF. Also, when running and bogging down at an intersection, the A/C stops blowing cold and engine almost dies... Does this help with further diagnosis?

[VStar650CL]

No, if it's bogging out the A/C will cut out just from low RPM's and low alternator output.

[kmikebennett]

Replaced both MAF's. Could not get the RPM's to go to 3K only. Driving was the same. Not over 20mph or 3K RPM. There seems to be a knocking coming from motor. Sounds as if something is loose and banging around. Sometimes it does it and then it will stop. Will try to upload video.

[kmikebennett]

https://youtu.be/GM-ufda3iIQ

[kmikebennett]

https://youtu.be/wME8oC28YsU

[VStar650CL]

Have you checked the exhaust yet? Metallic banging that isn't rhythmic often means a cat is disintegrating and you're hearing pieces knocked around in between the front and rear cats.

[kmikebennett]

I have had the CAT replaced 3 times in 3 years. Could be that. Can that keep it from going over 20mph? Also, can I check without a vacuum gauge?

[VStar650CL]

can I check without a vacuum gauge?

Not easily. You can check temperature on the cats, but that's difficult on a VQ.

Can that keep it from going over 20mph?

Your engine is an air pump, anything that keeps air from moving out will strangle its performance just like plugging the intake.

https://www.amazon.com/Hromee-Carbureto ... 595&sr=8-4

[macgiver]

Back to " knocking ", 8 questions Mike :
1) What oil IS SPECIFIED ?
1.1 On average , what is your oil change intervals been ?

2) Do YOU change oil ?

3) Do you goto a "quickie-lube " kind of place ?

4) IF you go to a quickie-lube , like $19.95 , or something , yes ?

5) Good practice to swipe on a WHITE napkin BEFORE & AFTER the job to see what's what ?

6) So .................64,000,00,000 question.......WHAT oil IS in there ?? Engine knocks , can be BAD , can come from OIL , INFEREIOR OIL ??

7) What would your opinion / knowledge be of those 50 gal drums in quickie lube ? Redline , Amsoil , Motul ??
I , respectfully now ...............................Believe it's C R A P !

8) Any other questions or findings on your end , ? Respectfully Mac

p.s. One of my cars spec @ 5-30 W FULL SYNTICHETIC , BUT just had 119 MAX degrees here , here we goto 5-40 W.....so adjustments like that + others can be done , ya ?

[kmikebennett]

I purchased the gauge. Where would the best place to test. I can't find a line to use.

Thanks!