hesitation

87 Z28 5.8 TPI hesitation problem @ 25mph. what could it be? Fuel injector/pump, head gasket, distributor, timing chain???. Recent tune-up, changed plugs, cap and rotor and wires again. Also, the fuel filter was
changed. Car does not die out with the A/C turned on. Reset the timing (without the ECU plugged in of course) Seems like the timing changes once in a while so could that mean its the timing chain? Several people have told me that is rare to have to change it. One person said it was the head gasket, another told me the fuel injectors.
Thanks in advance
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.