I bought a 07 infinity g35 sedan.
There was a hesitation problem that cleaning the MAF sensors cured.
112k miles, so I replaced the fuel pump/filter and plugs.
Everything was fine, then next day was hard starting.
I have checked several things including upgrading to the $17 spark plugs. Including battery and alternator check.
Took it to Midas and got screwed for almost $500, but problem still persists.
Yesterday I noticed loss of power.
I relearned accelerator position.
I reset ECU.
I haven't gone back to the "new" fuel pump/filter because, when I disconnect battery for extended amount of time, it starts normal and now have power back, but, after starting a few times it is again hard to start. I have disconnected battery to check things at least 5 times and every time the starting issue goes away, then comes back after about 4 starts.

 

Why?

First learn how to spell Infiniti.

You did not purchase a speaker.

Did you test the fuel pump pressure prior to replacement of the fuel pump>
Did you use OEM plugs?

That is where the incompetent previously employed at Jiffy Lube go.

Did anyone check for any codes?

Have you ever thought of following the troubleshooting steps of hard starting in the FSM?

http://www.nicoclub.com/service-manu...7_G35_Sedan/ec

"The crankshaft position sensor (POS) signal is not detected by the ECM during the first
few seconds of engine cranking.
• The proper pulse signal from the crankshaft position sensor (POS) is not sent to ECM
while the engine is running.
• The crankshaft position sensor (POS) signal is not in the normal pattern during engine running."

Randomly replacing parts, just guessing and not using logic is not going to solve your problem.

Check the following.
• Check camshaft position sensor
(PHASE) and circuit. Refer to EC-262, "
Component Inspection
"
.
• Check crankshaft position sensor (POS) and circuit. Refer to
EC-257, "Component Inspection"

You could also have a problem with the ECM?
.

The $500 that you wasted at Midas would have been better spent at an Infiniti dealer with a trained technican using their Consult lll tool to find your problem.

Just my $.02

Telcoman

 

Dealer diagnostic fee is usually the same as any of your generic shops, the only thing that is more expensive is the actual PARTS they replace, and some of those parts (like cam/crank sensors) it's STRONGLY recommended to get the actual OEM parts.

Personally I'd start with getting the battery tested, alternator run-tested, and the battery cables cleaned (both ends of each cable). Use anti-oxidation grease on the battery terminals.

 

Did you ever figure out what the problem was. Mine is also doing the same thing. It takes a little too long and it hesitates a little bit right before it starts. I also think it idles high, i think it idles at 2100 which seems high to me before going down to 750-1000. The car runs fine, doesnt hesitate or anything just cranks with the little hesitation before start. It sometimes is better on the starts after the first start but not always.

Battery is only a few months old. Dunno how to test the fuel pressure.

 

Idle should be 650 +/- 25 I think. Does the engine crank quickly or sluggishly?

Cold start idle is irrelevant, the engine will be whatever rpm it needs to warm up and 2100 isn't high.

I would start by finding the vacuum leak you probably have, then changing spark plugs and cleaning the MAF, then performing the ECM and idle air resets as detailed here.

https://nicoclub.com/archives/g35-35...procedure.html