Hi guys,

Hopefully someone can shed some light on this. Driving along the motorway last week and everything is running nice, then while in 5th gear and relatively slow speed (50ish) I start accelerating and hear a slight pop and a little miss!

It only happen once and then everything goes back to nice.

 

It then happened again this week. Exactly the same situation, only at slow speed in top gear and trying to accelerate, then back to normal.

 

I should probably have changed down, but it has never happened before and doesnt happen in any other gears :sad:

 

I have checked obvious things like leads connected etc.

 

Could a sensor of some sort be on its way out?

 

Ben

Its now developed into rough running at idle!

Still revs ok but not smooth.

 

Does anyone have an idea of what to look for first!

check all your PTU, coil and injector plugs for green/white gunk

 

this would give u missfires if corroded

 

Mark

Ptu?

Power Transistor Unit

its the item that sits on the front left of the cam cover

May be silver ( S1 ) black ( s2 )

as above injector plugs and injectors, coil plugs and coils, ptu connections etc etc.. If you find all these are good then if you have a leak tester then get some smoke bombs and check for any air leaks. Also check your PCV pipes in you rocker covers have not started to come lose. the one near the battery seems to be common fault

Also check your temp sensor plug on the front water pipes, if its corroded can be part of the cause of rough idle.

Thanks I will start checking connections. Probably not a coincidence that this has happened at the same time the damp weather came along!

Well I have spent the whole morning leaning into the negine bay, disconnecting any electrical plug I could find and cleaning them up. Some had the green gunk in but not anymore!

Problem is the rough running is still happening.

 

Could the PTU be failing?

Or the MAF failing

Is there any way of testing the PTU or MAF if you dont have spares?

Yes, with another one.... but you also need to clean the connectors on the MAF first....

also clean the CAS connector..

 

also do the vac test... (like ellodave said).... one of the vac pipes could have come off or be broken..

 

this might help you find stuff....

 

http://www.300zx.co.uk/forums/showthread.php?t=26120&referrerid=16305

BenB........ I work at Stansted Airport, and can come over to give you a helping hand if you want. Let me know buddy...... My email addy is: alan.goulding@hotmail.co.uk

 

Alz.

Is it not the old school test of spraying carb cleaner around the hoses and if the engine dies you have found the vac leak? it used to work on american stuff I have owned in the past,