bad hesitation

[matt38111]

hey guys having trouble with hesitation upon throttle on my 94 300z na. I am having so much trouble trying to figure out the problem as to why its doing this. I recently changed my spark plugs and used ngk irittium spark plugs. Also too i have checked all the coil packs and they are good. Has anyone had this problem or know what the problem might be. Im going to post a link to a video i made of my engine running below. Any help or suggestions would be greatly appreciated. Thanks!
http://www.youtube.com/watch?v=v7oFGAA4ewI

[emiliog2276]

Is that scraping sound coming from the engine or its the sputtering. Hows the idle when not being accelerated. Have you checked the ecu for any codes?

[matt38111]

I'm not too sure what that scraping noise is that was something new but it stopped. You can hear it better in the video when I put the camera close up. Well it's Idleing a little high right now because I need to adjust my tps. I haven't checked the ecu for codes either I've heard of it but now sure how.

[Ace2cool]

Maladjusted TPS can cause idle issues.

ECU codes, just peel the carpet back in the passenger floorboard from the top, take out the 4 10mm bolts holding the plywood floorboard in, and then you have access to the ECU.

Turn the key to the "ON" position, but don't start the car. Then turn the small slotted potentiometer with a flathead screwdriver fully clockwise, wait two seconds, and turn it counter clockwise. The Check Engine Light will flash codes. Long flash is first digit, Short flash is second digit.

So **Long long, long, short, short** would be code 32, or EGR.

You can google Z32 ECU codes for the full list.

[matt38111]

Thanks guys appreciate the info. Gonna give it a try today and I'll get back with yall.

[matt38111]

well the two codes that flashed today were the egr and the tps. im putting my money on the egr valve though because the tps sensor is brand new. well so far ive done some research and it seems like its going to be very difficult to to replace. ive heard that the best way to do it is to pull the whole engine out. any suggestions on a easy way to do this.

[GerryO]

EGR can be as simple as a disconnected/cracked/leaky vacuum hose between the EGR Control Valve and the EGR Valve.

There's also a simple test to check whether or not the EGR valve itself is leaking, which would also probably affect the idle.

http://home.swipnet.se/e-solutions/Vacuumleak.html

The TPS/setting is pretty important.

http://home.swipnet.se/e-solutions/IdleTech.html

http://home.swipnet.se/e-solutions/IdleTech2.html

Pulling the plenum might premit access to the EGR valve, but replacing it would still be a VERY tough job. At least it was on my J30.

[Chattzx]

There is no better sound than bad VTC gears. Such a dumb design, it makes it a PITA to replace them.

[matt38111]

Well I'm looking and looking and I cannot find this egr valve I've looked at many pictures of the location of it and it's not there.I'm guessing that the owner before me may have deleted it. Could this cause the ecu to flash the egr code? And could this be a problem with my performance.

[Ace2cool]

Yes, the EGR delete will cause a CEL. If the EGR was not deleted correctly, it may be leaking air into your upper intake plenum, essentially giving you a vacuum leak. That's a good place to start looking. The blockoff plates should be just behind the throttle bodies on the underside of the plenum.

[matt38111]

Ah all this vaccuum crap is so complicated! I need a Nissan expert.