noise at startup, rough driving at first part of accelerator

[theboy419]

after reading through the forum for this, i haven't quite solved atleast one problem but i figured i'd post both.I have a 90 240sx w/ the SOHC KA24E. I can't recall if it always did this, but it sure seems like it has since atleast april or so. When I start the car up, just for a second or two, it makes a weird, almost rattling sound. It doesn't last long and fades away quick, but just wasn't sure if it is something to worry about. I heard rumour of maybe a tensioner but wasn't quite sure how to check that out.My other problem i did find a few results and will try it out when my mechanic friend can take a look at it, but when driving the car, it seems whenever i start to press the accelerator or let off of it, just the very starting part of the pedal, the car almost violently shakes. I first thought it was the TPS, so i mentioned it to a mechanic and he felt it, said he thought it was the clutch slipping, which seems kinda odd to me since everything else in that system seems ok in that regard... anyway, i took it to a transmission shop today and they drove it, said the clutch feels great, its likely an engine problem, lol, so now i got back to square one... but did research on here and found maybe it's the EGR? Just wondering how to cehck that on the SOHC, how to fix it if it needs fixed? Also, before i forget, i read somewhere that a squeaking noise from the clutch is common to the master cylinder going out, just wondering how hard it is to replace the master/slave cylinder and the likes? Any help would be appreciated, thanks!The attached picture is what i think is my EGR, what needs pulled off and what step follows?
Modified by theboy419 at 4:00 PM 8/4/2005

[InsanityInc]

that's not your EGR valve, but it's part of the EGR system. That is the EGRC-BPT valve (Exhaust Gas Recirculation Backpressure Transducer). It could very well be the problem. But if you follow the vacuum line that goes away from the engine, you'll find a valve it connects to, that's the EGR valve.

[theboy419]

so what on that do i need to remove or whatever to test it?

also, is this the EGR? is the tube on top the one i need to disconnect?

[theboy419]

Just replaced the TPS, turns out that's all the problem was, for $43 my car runs great! Thanks for the help!