GAS CAP/PCV VALVE AND HESITATION

[MADMIKE]

Is it at all possible for a defective gas cap (not sealing or venting properly?)to cause hesitation? How about a PCV valve that's not plugged but may have a weak spring and/or be binding in the housing rather than sliding smoothly and freely up and down? Thanks all.

 

[eljefino]

PCV would just lead to funny/fast idle. Its only purpose is to cut a sizeable vacuum leak at idle to a smaller sized one.

The gas cap is a remote possibility but you'd hear a heck of a whoosh when you stop for fuel.

 

[mechtech2]

Describe the symptoms, not the answers.
Like when the hesitation occurs - cold/hot, light throttle, full throttle, etc., etc.,etc..

 

[MADMIKE]

Hesitates and "bucks" mildly but noticeably when warm under part throttle accel and steady throttle, not all the time but quite often, dealer unable to find any problem when they checked for codes ("diagnostic self-test"), I cleaned the MAF sensor with CRC MAF sensor cleaner (it looked clean to begin with), another clue is if I'm experiencing the problem and shut the car off and restart it the problem is gone. I've also tried 2 bottles of Techron, replaced the air filter, going to replace the PCV valve (Beck Arnley) and I'm out of ideas.

 

[MADMIKE]

The car is a 2007 Nissan Sentra Spec-V with 39,000 miles on it and it's a great car/engine when it runs right.

 

[Smoky14]

Vac leak or EGR over active?

 

[mechtech2]

OK Mike. Let's think about what is heat related. Ignition coils or modules can show failure with heat.
Possibly a fuel pump.
Also the throttle position sensor, or
a coolant sensor that is out of range -maybe a front O2 sensor.
And like mentioned, the EGR is still a suspect.
Vacuum or intake leaks , and injectors seals are always 'checkables'.
Sometimes things can be off and still not throw a code.

I am not listing all these things to be vague, but this is what we face when we have to determine a problem.