Im asking this question for my friend. He has an 04 G35X, 105k. When he goes to start the car and its cold, it starts fine. But once its warmed up and hes been driving awhile, it doesnt seem to start up as quick.

Could this be related to the spark plugs (they haven't been done on the car since it was new) or something else??? I am not entirely sure.

Thanks.

 

First things I would try are spark plugs, MAF/TB cleaning and ECU reset.

Spark plugs should be changed around 60k, so if hes at 105k and hasn't changed them its likely the problem. But also if the TB is dirty it could cause an issue, since the IATs will be higher on a warm engine, if a dirty TB is limiting flow the less dense air could cause an issue.

Tell him to try those things, and if that doesn't work give us a call.
-Rob

 

Define "doesn't start up quick?"

Do you mean it cranks slower? Cranks same speed but takes longer to actually fire up?

 

Make sure drive belts are tight to recharge the battery also, speeking from exprience this week you will have a starting issues and than a dead battery. My belts were loose

 

Cranks same speed, just takes longer.

Hes doing his spark plugs over thanksgiving, so we will see about that. I'll tell him to try the TB as well.

 

my car was doing this once in a while for the past 6 months. just threw a code 2 days ago. p0340 cam pos sensor. seems like the common thing. i also did tune up and all

maybe yours starting to go bad and hasn't thrown a code?