Hey guys I could use a little help with the truck. Here is the back ground info:
1996 F-250, 5.8, extended cab, 2wd, auto.
I bought it used this past March (2012). What I know the previous owner did to it: Shorty Headers, Throttle Body Spacer, Custom exhaust, no cat, K&N cone intake.
Smog pump still there but not plumbed
The problem; this truck has no guts. It sounds great but will not get up and go. Under normal driving, it seems to bog down on acceleration. When towing my boat (18ft Mako) I have to floor it to maintain speed on a slight incline, anything more than slight and I will lose speed. Towing this same boat with the wife’s Grand Cherokee or my old Dodge Dakota on the same roads I never had an issue, so I am sure this is not normal. It will sometimes die when you first start it, but then start up. It will also sometimes bog when you first start to drive it in the morning. It also seems, while driving that at certain points while giving throttle, it will move ok, but a little more, or less, and it bogs.
What has been done; did some fuel injector cleaner, replaced the radiator because it was cracked, it had bad ping so shop adjusted time from 14 back to stock (10). Had intake manifold leak, shop repaired and repair/replaced several vacuum lines. Replaced fuel filter.
I figure it may be ignition related, but before I just start replacing everything, I figured I’d look for some advice here.
Thanks

 

does it have a mass air flow sensor if so it could be very dirty seen some trucks do the exact same thing

 

No, it does not have the mass air flow sensor on this model.

 

Couple thoughts, recheck the timing with a timing light. Is there an O2 sensor hooked up?

 

I did not see an O2 sensor anywhere on the exhaust, but I did not look for it. I'll look today.
Thanks

 

Check fuel pressure and pull the codes.

Remove the TB spacer and throw it away, it's not doing anything usefull and may be interfering with proper IAC valve operation.

Also verify that the timing was correctly reset, a small jumper called the spout plug has to remove to disable computer advance when setting the base timing and if this wasn't done the timing is now way more retarded than it should be, and that will result in poor power.

 

Update, there is an O2 sensor, right where the two pipes come together into one. On the timing, I am waiting on a timing light to come in the mail. However, the truck had these problems before the timing was touched which leads me to think it is not timing related. Another question, the truck does not have a tach, do I need one to check timing?
Another clue, when applying even pressure to the gas to accelerate, the truck will hesitate a little, then after a bit, with same amount of pressure on the pedal, it will start to accelerate as it should. Also it has no top end, 70 or maybe a little more but you have to be going downhill and it'll take a while to get there. Just seems like it has no power but sounds great....
Besides timing, any other ideas?

 

Still looking for input.... I have not got the timing light yet so not much I could do. I decided to disconnect the battery and see what would happen. Disconnected it yesterday, but did not get to drive it. Started out to work this morning and it was bad. hesitated real bad and sounded like it was backfiring through the intake. I figured the computer was just sorting things out. It finally ran butter by the time I got on the highway, but I did notice once on surface streets again that it was again hesitating when trying to speed up slightly or maintain speed on an incline. Any more suggestions?

Thanks

 

See Paul's answer in Post#6. No sense going much further until you check the basics.

More reference info: Fuel Injection Technical Library » Setting the timing

 

Thanks for the link, what do I need to check the fuel pressure? I'm sure some type of gauge, and then hook it up where?

Thanks again

 

Stopping by AutoZone today to have them scan it and barrow a fuel pressure gauge.

 

Look for the test port on the front of the driver side fuel rail. This phot has a screw on fuel pressure gauge already attached:

courtesy of Paul Conanski

 

Ok, thanks for the photo, I found it. Where can I find a simple screw on gauge like that? So yesterday was a complete bust. Called AutoZone to assure they could run codes, told them it was OBD 1, they said yes they could, and they had a fuel pressure test kit I could barrow with a deposit of $160. I get to AutoZone and they look at the truck and say they can not test OBD 1......I take the test kit home and the only adapter I need to hook it to my truck is damaged and I can not use it......
I did get the timing light in last night and hope to check it tonight after work.

 

The link to the "fuel injection technical library" above has a procedure to pull the codes without a code reader. The readers digest version is put a small jumper(paperclip) between the STI and Sig_Rtn wires on the EEC Test connector found under the hood near the drivers side hood hinge, turn the key to run without starting the engine and then count the flashes on the check engine light. The codes will be flashed out twice seperated by a short pause, and the "stored" codes are seperated from the "realtime" codes by a longer pause and a single flash. You can turn the key off and restart the sequence as many times as needed to get everything copied down correctly.

The fuel gauge on the engine pictured above was purchased at Summit Racing and the fittings were sourced locally.

 

Although this sounds crazy, I had similar symptoms on my 88 F-250. Turned out to be an aftermarket ignition module. I put a Motorcraft one in there and all my problems went away.