HELP... poor acceleration

[paleahy07]

Sorry if I'm in the wrong spot, this is my first time posting.

I have an acceleration issue.. I have a 95 z32 NA. All stock no mods.

The problem I'm having I've had for a while. It used to be very intermittent and it only happens when the car gets hot or sits in traffic for a few minutes.
If you give over 40% throttle it starts to choke up and wont really accelerate till it hits 2500 rpm then shoots off . But if you ease into the throttle it will accelerate normally as if you were driving it slowly.Being this problem used to be very intermittent i never payed much mind to it.
Recently i had done the timing belt, spark plugs, put dilectric greese on all the connectors, cleaned the MAF and changed the battery. After doing so this problem has become a constant... But only when hot

I have rechecked the timing marks and they are lined up perfectly.
I pulled codes and i have a 34 (knock sensor circuit).
I put on a new CAS and adjusting base timing ignition to 15 degreese BTDC.

I have tried keeping it in open loop by disconnecting the 02 sensors and the knock sensor (at seperate times) and acceleration only gets somewhat better.. not by much.
At idle it seems to run lean

when you give hard acceleration the scanner shows the ignition timing is being pulled down to negative 26 degreese.

I know this problem is due to the ignition timing being so retarded but what the hell could be causing it to go so retarded only when its hot?

Thoughts and suggestions would be much appreciated!

[NolimitZ32]

Have you checked for vacuum leaks?

[paleahy07]

Yes there are no vacuum leaks present. I sprayed all around with carb cleaner and looked at all the lines and I have nothing

[NolimitZ32]

That's not 100%. If you have conditions where under load or when warm the problem manifests this means that it could be an intermittent vacuum leak that appears when more vacuum is introduced to the system or when the hose or gasket expands and the hole opens up. The carb cleaner method is great for simpler engines, but the sheer amount of vacuum lines and complexity of the systems in a Z32 make it more voodoo than a proven technique. The only proven technique for finding vacuum leaks is through the use of a smoke machine but that's a whole other can of worms. Have you ran the codes from the ECU?

[DCaff300ZX]

^^I think he said he had a 34, knock sensor.
I had this problem once way back with the NA, and be damned if I can't remember the solution. It may have been my one hardpipe that had a split in it at one of the vacuum bungs I finally replaced, and also could have been when I did a FPR and fuel dampener change. The dampener is affected by heat as I remember and important at under running conditions to keep the fuel supply steady, so check those two just for "why not" purposes.
Also as NoLimit said the vacuum hunt is not easily done by spraying or otherwise, but by replacing hoses and checking the units on either end for correct operation. The IACV can give some odd operation under hot conditions, and corroded connectors is a constant issue and can be involved if not the cause of a myriad of issues...check them all for green corrosion and clean/replace as necessary, ESPECIALLY if the connector is broken.
Hope this helps!

[paleahy07]

Thanks for the suggestions. I'm gunna see if disabling the egr will affect it at all as well. I'll get back to this when I have some time over the next few days