Potential vacuum leak, alternator, IACV, something, idk...

[ChaseOfSpadeZ]

Ok, here are all of the issues combined into a single list as to help someone who actually knows what they are doing identify the issue and maybe throw some advice my way.
1. Had my Plenum and Valve Cover gaskets replaced about a month ago, started noticing gas milage decrease after the work followed by some cold start issues. Also, now my oil pressure during idle sits around 20-30 psi. During acceleration it hops up to over 60 and above.
2. Once I started to smell gas around cylinder 6 I full on thought injector leak. Took it to Z Fever and the guys there found a bad fuel line the original mechanic didn't replace. They fixed that issue there.
3. Cold start issues and fuel smell went away, but my RPM's started bobbling up and down around 1k as I apply the brakes, my lights will dim, AC fluctuates, and occasionally the steering will stiff up. The oil pressure still sits around 20-30 during idle.

Is there the slightest possiblity that the car is just adjusting to the higher fuel content applied and is attempting to compensate?

I was planning on actually doing some upgrades this summer but I'll be lucky if I can just get a decent running car again... I'm stuck in Florida for the summer without a garage or tools. This, combined with my shot carrier bearing, is going to end up costing me a fortune. PLEASE HELP! :/

[ChaseOfSpadeZ]

Well, it's not the alternator, the brake booster line looks new. I guess I'm just going to smoke out the hood and see if I can find a leak. If I can't, I have no clue where to check next.

[t.mcginley.jr]

Have you checked for any error codes yet?

http://www.nicoclub.com/archives/nissan ... ostic.html

If you think its any kind of vacuum leak, you should definitely buy this:

http://www.z1motorsports.com/product_in ... ts_id=1867

With the boost leak tester you can easily tell if you have a vacuum leak. Plug it in where the MAF normally goes, pressurize it with ~10 lbs from an air compressor and listen for a leak.

As for the carrier bearing, what do you consider a fortune? A new one-piece driveshaft can be had for $260 shipped (or $275 if you have a 2+2)

[ChaseOfSpadeZ]

Holy crap, I didn't know all that about the ecu diagnostic! Learned something new. I'll try this out tomorrow, thanks!

Also, where can I find a one piece this price? Everything I have found is $350+ I'm looking around for a used one right now too.

[t.mcginley.jr]

Driveshafts:

http://epracing.net/products-page/drivetrain/

EP Racing is owned by a guy named Mitch, he's a really good guy he does all of his own machine work. He can pretty much do anything you could think of to our cars

[ChaseOfSpadeZ]

Thanks man, just placed my order. Some how the idle issue went away. Picked up a foggy headlight and a t-top leak since yesterday though. Can't seem to keep up, lol.

[DCaff300ZX]

The idle issue can easily be corrosion in your PTU/CTS wiring harness connections and/or injector harness connections, especially after the work you've done and issue "going away"- after similar issues I found my second PTU connection was awful while the first was perfect and was a 5 minute fix. CTS was also iffy and that helped a lot as well when perfectly clean and di-greased.
Your dimming lights also suggests that your alt may be nearing it's end even if it "checks out" OK, I've had two pass tests but die soon after and any issues beforehand go away with a new alt...may have to do with our drip-down issue from the ps res. Also, again check all connections there as this can also lead to having the alt on too often trying to recharge your battery but the bad connection will not allow a full charge.
Good Luck, hope this helps!