It happens when I press on the gas from a complete stop and while I'm holding a speed at low RPM.

From a complete stop, say at a red light, the hesitation period varies. The shortest being 1/2 a sec. and the longest lasting almost 3-4 seconds. Right after it gets itself together, it pretty much launches me forward because I've pressed the pedal down for a good bit at that point.While I'm holding the speed, it lasts as long as I'm at that low RPM range, roughly around 1000-2000.

A little background, it is an automatic, H23A1. The spark plugs are new, all gaskets have been replaced, head was machined and has had the valves changed according to the seller. I've got a general understanding of cars but from V8's since I've driven them all my life. My mom's Expedition had almost the same problem and changing the spark plugs fixed the problem there. Unfortunately it didn't work here.

Any help would be awesome. Also, first post

 

Calibrate the TPS? Sounds like the throttle position sensor (TPS) may not have gotten put back exactly right or was replaced and needs calibrated. Search for that and you should be able to find the procedure. Also, if that doesn't work, you may need a new TPS, then make sure you cal it after install. If not, as you open the throttle, the computer won't know to add more fuel, so it hesitates.

 

Could be egr related. Pull the egr valve electrical connector and when it throws the code, which turns off egr, see if it still does it.

 

I'll add both of those to the list of things to do for the weekend. Any other theories I could test out?

 

Also, would replacing the cap, rotor and wireset do any good?

 

Wiresets go for a long time, especially if it's NGK or OEM. Just go cap, rotor, and plugs.

 

I am a bit confused, is it the engine hesitating, or is the engine building some rpm, but the car isn't moving?

Sounds a bit more like a torque converter or tranny issue should be examined as well at this point.

 

Open up the distributor cap and check to see if your rotor has come loose because the screw holding it down might have backed out.

 

No, its hesitating. Although the tranny does have some rough shifting while on the road. I'm not tackling that though since I'm converting to manual in the near future.

I'll definitely check that out. Anything that saves money is a good thing