Hesitation at WOT in 1st!?!

[LX5liter]

Originally posted by daman007
sorry to say this but many times when you put a bigger manifold and better heads you will run into problems like that unless you go all the way. leave it stock, a stock moter with a bit of work usaly runs way better with the stock manifold, reason is, hear you are dumping fuel at a faster rate down BUT your air and mixture is all wrong, now im not saying this is the priblem im just going by exp, i remember once doing sn old 340 dodge an an old 302 and on both i did the smae mistake whent out bought bigger carbs, performer manifolds and the car ran worse no kidding $800.00 for nothing actually worse cause when i raced i would never race from a stop but only on rolling starts, i was a kid then so who knew. the one thing that will probably help is a new chip and get it set up by a real good set up guy, bigger injecters will make it worse not better. id bet if you put the old manifold back it would run way better and then you will feel the power of your built up heads.

On an injected motor the computer is constantly adjusting the air/fuel mixture (to a point), so it is easier to change things without messing with the fuel system. Carbs are a different story as daman007 says, it takes a lot more tuning to get things right, but your still injected so we'll go from there. Your hesitation could be a fuel pressure issue as well. get an adjustable regulator and a gauge to set it with. Try bumping the fuel pressure a couple of #'s at a time to see if it helps or gets worse. Have you checked the TPS with a multi-meter to make sure there are no dead spots where the voltage jumps? It should rise smoothly from about 0.995 vdc to around 5 vdc as you open the throttle.