94 F150 4.9 Maybe 150mi on fresh rebuild.
Was having all sorts of surging problems but have that fixed. The truck loses speed in OD when i am running say 65 and come to a hill. I push the throttle and it just won't hold the speed. I can let off a little and just barely touch the pedal and it seems to do better. Could it be the timing, I have it at 10deg. I just replaced the EGR and Sensor, a vacum line going to the solenoid for EGR, Coil Wire and that got rid of the surging. Now this very sluggish top end stuff. HELP.

 

I assume it is still stock EFI, so first step: check for codes.

 

I don't know of any OD that was ever intended to pull hills with.

 

in od you will not hold that speed up hills..just drop her in 4th and you will be fine..

 

Fella's this is just normal hills. Down the highway. Not big hills. I can let off the throttle just a tad and ease back down and it seems to pick up some. The pedal aslo has a dead spot from idle, when you try to rev it up. I cleaned the whatever it is on top of the throttle body. It sits right on top at the end of the air filter tubes. Didn't seem to help.
Thanks for the responses thought for sure someone would just know right of the top of there head lol.

 

ok well then i would suggest your tps...that would take care of the dead spot you are talking about and maybe the sluggishness

 

Well, normal hills to TX might not be the same as normal hills to IA or WA or PA...and there is what would be considered normal in TX hill country which might be a different normal than that for the country between Amarillo and Ft. Worth. At any rate, OD is purely a flat lander cruise gear. A vehicle in OD that sees grades as little as 2%-3% might start choking. If it sees a grade like Lewiston or White Bird in ID...I'm sure im2tall33 knows about them...it will just about die of fright.

 

I understand just don't think the hills i am refreing to should in no way have to shift to
4th gear. It only drops a couple to 5mph. And to me should have no trouble holding the speed of 65 at all. I know i am having some top end issues. I will run the codes again. My check engine light did not come on even when i was having such violent surging problems. It does work when running the codes and also when turning the key to on. Man pulling a small boat would not be very fun lol.
2tall i am guessing you may be correct. I have been all over the U.S. and have spent many vacations in Colarodo. I do know what a HILL looks like lol. And could understand going into 3rd. Went up and down one road frome Lake City Colo. to Uray (SP) 16mi. took 5 1/2hrs. Brakes were burnt and smoking like crazy. I was in a 4wheel drive Durango the road said 4x4 needed and man they ment JEEP high off the ground 4x4 lol. I will run the codes one more time and hope the TPS does the job. Thanks again fella's and hope i can help out someone in the future also.

 

What rear end gear? I've got a 3.55 and only have to drop to 4th going up a 5% grade or steeper. 5th gear should handle a 3%-4% grade easy @ 65mph, unless you're carrying a lot of weight and/or you've got 3.08 rear end. Or really tall tires?

 

205 75 15 Not for sure on gear. I know it should not drop on the small hills i am going up. Even on flat ground it just has no top end power. It seems like it struggles to just pick up speed from 55 to 65. I give just a tad of throttle and it seems to work better than say 3/4 throttle. It is like I have a dead pedal even if i put it to the floor it still loses speed i can let off barley touch it and again it does better.

 

I went back to the original post and it states that you have ~150 miles since rebuild... did the problem of losing speed on hills exist prior to the rebuild?

The question was asked by Roader about which rear end gear ratio... as a point of reference, my son has a 1984 F150 with 4.9L and SROD [4 speed manual OD], which came with 2.47 rear gears. At 65 MPH, it was only turning ~1300 rpms and would require downshifting to 3rd at just the sight of an upcoming hill.

 

Only 150 miles on rebuild? Give it some time...and miles. It will eventually break in. Or, you could take a trip to CO, go up I-70, turn off on Hwy 6 and go over Loveland Pass and by the time you got back to TX it will be running just fine.

 

Harte3 i have been over that road and yes it would be broken in for sure lol. Went over that pass just as they were closing all the parks for the season had to take a RR break and they were waiting for us to get out to close the gates. Was around Sept. 3rd. Found the road when a major rain storm hit and we just pulled off into George Town for the night. Was spectacular views though. Love Hwy 24 also. And going frome Grange to Estes Park would also do it I think lol. We have been all over the state frome top to bottom.
Now hopefully it is getting broken in and will start responding on the 2% grade hills. I just have no response when i hit the throttle pulling these very small inclines. I will get her figured out though. Thanks to everyone and if anyone reading this happened to have had this problem and can give me some insight sure would be appreciated.

 

1986 I don't know I bought the truck for 400.00 with a bad motor so i really don't know anything much about it. The lady i got it from said her friend was supposed to be taking it to get it tuned up, and went off and got drunk in it and she had to have it towed. I cranked it just before starting rebuild. When i pulled the drain plug on pan NOTHING came out and the pan itself was DRY no oil film just some copper off the bearings it ate up. Had one blown piston, replaced two, crankshaft, camshaft, lifters, rings, bearings, oil pump, etc. Did nothing with the intake or throttle body. Cranked it up on 5 cyl. my brother inlaw didn;t plug all the injectors up. It ran real rough lol until i happened to see the injector was not plugged up. Then it surged real bad got that fixed. Now just no top end even on flat ground struggles to go from 60 to 70.

 

This is good advice... you might have already done this, but I did not see that you have.

What about the exhaust? If the catalytic convertor(s) is/are plugged, your engine will "run out of breath" real soon. My 1986 with 4.9L, 4 speed O.D. [SROD] and 3.08 gears easily will cruise @ the speeds you mentioned [60-70 mph], but I normally cruise @ 55-60 for gas mileage [our trucks are shaped like a brick and do not glide through the air].