Weird hesitation?

[circaz1291]

I have a 1990 300zx NA that's always had this hessitation problem. I've gone through an extensive process to try to solve this issue but still have not resoved the hessitation. The list of the parts I've replaced so far to fix the issues are: Rebuilt engine, injectors, fuel pump, IACV, TPS sensor, O2 sensors, PTU sensor, coolant sensor, fuel temp sensor, crank angle sensor, MAF sensor, all of the ecu wire to go with all the sensors, new spark plugs, Z1 air intake, all fuel lines and vacuum hoses have been replaced in the engine bay, Z1 clutch with flywheel, and complete exhaust. I'm probably missing a few things but I literally almost everything and I still have this hessitation issue. It only happens when it warms up and only in the first part of acceleration and after 3000rpms the hessitation quits. When it does hesitate it jerks and makes a fast popping sound. One more thing if I hold the peddle down about 10-30% then thats mainly where the hessitaion is coming from, if I push it passed that or to the floor it jumps out of the hessitation. It's really odd and I'm not sure what to do now lol. Any advice or help to pointed in the right direction would be much appreciated, thanks guys.

[elecfus]

it could be the cam phaser or timing being out of alignment. get a timing light and check the consult matches what you read with the light. also check the TPS is correctly calibrated according to what you read on the consult as the throttle position sensor is a part of the feedback for the EGR and cam phaser.

[rgregoryb]

Google "Premier Z 300zx hesitation"

[elecfus]

Google "Premier Z 300zx hesitation"

that either tells you to read the entire manual or links back to this forum telling the owner to just take it to a shop fyi.

[DCaff300ZX]

it could be the cam phaser or timing being out of alignment. get a timing light and check the consult matches what you read with the light. also check the TPS is correctly calibrated according to what you read on the consult as the throttle position sensor is a part of the feedback for the EGR and cam phaser.

After all of the work you've done I'd bet on the TPS being slightly out of adjustment, a fairly common problem I've heard because the setting can be just off and seem right, but cause issues...use the FSM and be SURE to set the TPS correctly and see what that gets you...only other thing I can think of is a bad CAS.