Hey Guys,
I have a 92 SE-R. I put a JDM motor in it and it has not run right since. My problem is this: When you first start the car is idles kinda high and then after a minute or two it idles down to ~800-900. It has a very lopey(irradic) idle. After the car gets good and warmed up the car with hesitate, bog when you try to rev it, and just basically when it gets good and warm; it will stall....no matter how much you feather the throttle. I have changed out the Coolant Temp Sensor, Distributor, MAF. I have adjusted the tps so it is within specs. When it starts bogging when you apply the throttle, the check engine light comes on....and it mainly happens when i rev'd the motor. I checked the code and it came up as a knock sensor. So I don't know if that is telling me that the ecu is picking up knocking, or the sensor itself is going bad. I was going to check the timing and the timing was all over the place at idle. I don't know if that is because something is making that happen or if the irradic idle is causing the timing to jump.I need some REAL help from an expert. I have had 3 shops work on it in the past year and NONE of them have "fixed" the issue. So basically 3 shops and 2,000 dollars later; I have a car that is still not driveable for more than 30 seconds. I am about fed up. I would hate for this car to be sent to the junkyard.
-Nick

By the way, I have checked every vaccuum hose and every sensor is plugged up. I figured if I would have missed something....the three shops that had it would have caught something. I have searched and tried everying I could think of. If I have time after work I will try to post a video of what it is doing.Thanks in advance.

are the cams installed correctly?
have you tried a new ECU?
Timing does jump around on a normal car at idle. You have to put it in "timing mode" to check the timing. There is a routine in the FSM or you can get a Consult scanner.
It sounds like you have air leaking into the intake after the MAF, which is unregistered air.
Are your spark plug wires going to the correct terminals on the distributor cap? Have you compression checked the engine? You have good park plugs in there?
Also, you could have clogged fuel system, leaking injector O-ring, bad fuel pump, etc.
If you get really desperate take it to a Nissan DEALERSHIP and pay them to diagnose the problem, then you take the car home and fix it.
THere are a thousand things to check, so get busy.

i have not tried a new ecu. I figured that if that one was going bad that it would flash a code. compression check is fine. cams are installed correctly. I just dont understand why it would rev fine and freely till the car gets warmed up good. I don't think it would have anything to do with the fuel system. I just replaced the fuel filter 2 days ago. I know my spark plug wires are going to the correct point on the distributor cap. There shouldnt be any unmetered air entering the manifold. But I will check as soon as I get off work. Just curious, you don't think this is an ignition or knock sensor problem??

did you swap over the AAV on the passenger side of the motor, right ont he side of the intake manifold? you got to swap that out too. i'm in the process of swapping all my usdm sensors to my jdm before i install the motor. could also be your maf is bad.

Did you swap over the knock sensor??? Mine ran like shit until I got that switched.