When I first got my truck it sucked bad. It wouldn't hold 65 in OD with a small head wind and there aren't any hills on the Texas coast just bridges. It had 3.08s in it then. After I did a tune up it didn't do much better. I took it in to a mechanic and he replaced the IAC, TPS and something else and it made a world of diffrance. A few years later my truck started to go back down hill. I replaced (in order) the IAC and TPS, FPR with motorcraft parts, and oxygen sensor, and my truck got even better. Then I swapped my 3.08s with 3.55s (about 2200 rpm at 65mph with 31in tires) and had to raplace my ingtion mod and coil a few months after the swap because it they decided to go bad 30min from the house. I use to not be able to pull a 3500lb 20ft trailer very well but now my truck can do it with out a problem. I also pull 14-15 mpg mix driving.
If I get any new sensors I go with motorcraft if I can afford it or BWD. Cheap parts are cheaply made and will eventually lead to failure. But you also said that it is a new motor and I don't how many new parts you used on the rebuild and the motor isn't broke in yet.

 

Hunt 89 That is very good info. I will be replacing the tps, IAC, and the engine coolant sensor. After it is driven say 10 mi. and sits for 15 min it is very hard to start. It will crank right up after it cools down or if i start it right up after killing. I know the coast also and not alot of difference here just normal highway hills that in no way should lose speed on i O.D. The rebuild consisted of New Crankshaft Kit, Camshaft kit, 2 new pistons, oil pump, Rings, Hone job, normal rebuild except not all new pistons. One piston had a hole, and i dropped one and broke the skirt. When i crank it up it has a dead pedal also. Give it gas and it has a blank spot then after I rev it up a couple times it goes away and drives fine other than dead pedal even on flat ground after about 60mph. I can let off and just give it a tad of pedal and it picks up better than if i try to go on down on the pedal. This is the very first EFI i have ever worked on and trying to figure out what sensors are causing the problem is frustrating not wanting to end up replaceing them all because of funds, and i know they can't possibly ALL be bad. I keep getting the EGR code and now 15 I replaced the EGR and the sensor and the vacum solenoid from all the tests i have run is operating as it should. Temp and normal operating temp vacum goes up to 7hg when i give it throttle driving down the road and goes to nothing soon as i let off as it is supposed to do. I am lost, Hope it is not the pcm not working properly. Thanks though i will try to check these out before i spend the $$ for them.

 

Just to give you something to compare to, I also have a 94 but in a van.
I live in S Florida so about the biggest hill is an overpass.
Idle vacuum is 21", in gear 16" (automatic C6 with 3:55 gears and taller tires), cruising at 60mph 15-12", going over overpass at 60 mph 5-8" (depending on how far you push the pedal), full throttle 1".
In the above the pedal is rarely pushed more than 1/4 way, if more it goes to anywhere from 1 to 3"

I run with a vacuum gauge all the time. Good indicator of engine health.
BTW, check all your vacuum plastic lines, they have a bad habit of cracking affecting performance. I replaced all mine with steel brake line and rubber.

 

Fuel Injection Technical Library
Here is a link where you can learn about the sensors and how to test them.

 

Thanks Hunt i already have that. I have tested and retested the EGR and it seems to be fine. The others I am in the proscess of testing and some i have to get more stuff to test them with lol.

 

I have checked about everything the code is still EGR but have changed it did electrical test, and vacum test everything on it seems to be working fine. I did every test the Fuel Injection Library suggested. I still lose power up hills SMALL hills and when give it full throttle have a knocking, pinging, rattle noise. Does not matter what gear i am in when i give it full throttle it just does not pick up. I can let off just a little and get back in it and it picks up a tad but then the rattle starts and it still does not seem to be getting fuel. I am so lost on this. Makes me feel real dumb lol. Anyone know anything to try. Could the TPS cause this or the MAP sensor. I don't understand exactly what the Library is saying as far as testing the TPS sensor. I don't know what to check exactly, or where it wants you to check it.

 

Remove and plug the green vacuum line that goes to the EGR valve. Drive it and see if the throttle response is better.

 

Hard starting when hot, could be due to leaking injectors, the 300 uses the same ones as the tempo/topaz 2.3L and they seem to be prone to leaking. "One piston had a hole" That indicates detonation before the rebuild... Check and verify the timing is at 10 degrees with the spout connector removed, and check the fuel pressure, if you have dual tanks try switching over to the other tank to see if things improve.

tiap's mention of how much vacuum the engine is pulling at idle/light load conditions is also a good indicator of how its running. if the vacuum is very low you could have plugged cats.

 

How do you check the engine vacum. I mean where do you check it. I have vacum guage just don't know where to hook it for checking the engine vacum. So many vacum lines lol. I will try unhooking the vacum from EGR But I hooke a the vacum guage to it and drove and it was as the link above posts said should be.

 

Connect gauge to a "manifold" vacuum source.

 

One of the ports on the vacuum tree on the plenum across from the throttle body.

 

The noises would suggest that you are running either very hot, very lean, very advanced on timing or all three.
Check to male sure you balancer outer ring has not slipped and you are setting incorrect timing.
Check your coolant temps with an ir gun at the tstat housing.

 

My timing was off. I have looked at the Harmonic Balancer and will look at it real good this morning. I set timing again and it ran better but still loses speed and dead pedal on the small hills. I am going to check the fuel pressure today also. I am pretty sure it is not getting hot just from messing with it right after driving. Wonder if i need to set the timing a little more advanced than normal. Or retard it. I have to be doing it to know which way is what lol.Thanks for all the advice. I will get her figured out sooner of later. It is almost just right.

 

Regarding the harmonic balancer... use a piece of chaulk and mark a straight line across the front. Drive the vehicle and then look at the line. If it is not continuous, the rubber to metal bond has failed and the rings are moving.

Every engine has different timing requirements. The factory specifications are for a stock new engine. Usually, stock engines can benefit from being advanced a little [2 or 3 degrees], but as you drive, if pinging is detected, the timing will need to be retarded. Some people use a vacuum gauge rather than a timing light to find out "what the particular engine likes".

Remember, on the 4.9L/300 engine, to advance the timing, the distributor is rotated CCW and to retard, turn CW.

 

Looking forward to seeing where the fuel pressure is at.