Runs, drives great til it gets to temp???

[ahstrong57]

I have a 1993 nissan hardbody w/the 4 cyl. z24i
engine. It runs great when its cold and when iam in neutral but when i get to temp at around 2500 to 3500 rpms it begins to run rough, especially when under load (driving), i know its not a leak in the intake manifold, clutch, spark plugs fuelfilter, cylinder comp. i have new fuel lines, filter, ect., If the timing is right on startup would'nt it be the same when it warmed up?, my buddy says throw parts at it but i was wondering if any of you guys have experienced this before??? This is

[StephenG]

I'm not familiar with the carbed nissan engines at all so this might be completely random but do you think fuel starvation might be a possibility? Perhaps its time for a carb rebuild.

Edit: Haha, Whoops. Told you I know nothing about the z24s

[seang]

The z24i is not carbureted, it is a TBI unit. It looks like a carb until you take the lid off the air cleaner.

I would check the heat riser (the tube that directs incoming air over your exhaust manifold to aid cold starts). The check procedure is in the service manual, which is downloadable from Nico, free to members.

http://www.nicoclub.com/FSM/

[longtooth]

I would also check your spray pattern on your fuel injectors. Sounds like a lean missfire. Also how old is your o2 sensor or was that replaced as part of ect?

[RT22]

free stuff first check for cracks in all vacuum lines. vacuum leaks can cause such stuff. POP dist cap and inspect it make sure no cracks or corrosion.