93 Hardbody misfire

[nomadcat57]

I have a 93 hardbody with a ka24e. I am having problems getting the vehicle smogged. When the engine is reved to about 1800 and above a missfire starts. (runs strong and clean at an idle) Shops think that it is leaning out and that is causing it. (Now have to deal with the gross poluter labe until fixed) I have checked all the wiring for the injectors from the computer to the injectors they are all fine. The plugs are newer and have good spark. Computer diagnostics come up with nothing no check engine light. Out of ideas as to the possabilities. Any help would be greatly appreciated.

[Rev_D21]

How are the wires? What is the cap condition?

[nomadcat57]

cap and wires are good, replaced in dec.

[Rev_D21]

Have you watched the timing with a timing light while the misfire is happening? Have you replaced the vacuum lines anytime during the trucks life, those get old and crispy after a while. Vacuum leaks can cause all sorts of fun.