okay. it only happens when its warm and runs fine past around 2500 rpm. when i accelerate especially from a stop. she boggs and or misfires and has very hard time gaining rpm. with more throttle the more it boggs until i get the rpm up and its worse on hills. no ses light and it appeared overnight after jump starting it and replacing a fuel pump relay. i think i may have knocked something loose or pulled on some wires but couldn't find anything. i replaced the tps, map sensor, and the coolant temp sensor but no luck. im thinking its my oxygen sensor but at this point im just looking for wiring faults. the eec relay is right beside the fuel pump relay i changed and i disconnected them both to get them out. the eec relay does have a wire going to the oxygen sensor so there could be some black magic nonsense there and thats as far as iv gotten. distributor is fine. at idle its fine and i checked all cylinders are firing at idle and i just don't think its ignition or injectors since it happened overnight. i suspect wiring to coolant temp sensor, oxygen sensor, and wiring to oxygen sensor. id apreaciat the input cause im running out money for sensors that dont need replacing. thanks

 

I think it's always best to start with the plugs/wires/cap & rotor, when dealing with an under load problem. Nine out of ten times, ignition is the problem, and can come on suddenly as you described. Wires really only last a couple or three years on average, with plugs close behind. Wires dry out, crack, leak and develop resistance in them.

 

Instead of blindly throwing parts at it you should have checked for codes. Many times there can be a stored code or issue found during the KOEO tests WITHOUT having a Check Engine Light (SES) on.

 

As RLA said, check for codes first. Then let us know what they are.

townsend, what year, engine etc is your vehicle?

 

thanks for the replys

its an 1989 f350 with a 460 and yes i probably should of bought a code reader instead of parts il work on that. if it was wires or plugs wouldnt it do it when its cold too

 

could the coil be on its way out cause iv heard of bad ones missfiring under load

 

Ok, tell you what...go buy all the parts you want until you fix the issue.

We told you the preferred path to resolve your problem without tossing more money and $$parts$$ at it. It's your money and a free country. You asked for advice, we gave it to you. If you are not going to follow it, it's your prerogative but do not keep coming back to the well for more advice until you follow some. For me, I'm tapped out. I wish you the best of luck.

 

ok, tell you what... il go buy a $$code reader$$. thanks and i appreciate the replys, hopefully slip man ford is right and its just something ignition which from how its starting to act is pretty spot on. thanks

 

You can get a real decent one for 30.00, Amazon.com: Equus 3145 Ford Digital Code Reader: Automotive and you can pull the codes without one if you want to. Ford Fuel Injection » How To Run a Self-Test...An ignition check up won't cost you anything, just some time looking at the spark plugs, and maybe testing the wires. Its just best to eliminate that possibility first thing, before spending a lot of money.

 

This.
You don't have to spend a dime, just some scrap wire and about 30 minutes of your time.

 

thanks that sound like a much better idea i appreciate the advise

 

thanks for the link. i ran a self test and these are the codes i got

koeo
85 Canister Purge Solenoid circuit failure.

cm
22 MAP/BP sensor out of self test range.
32 EVP circuit has intermittently failed below minimum voltage of 0.24 volts.
95 Fuel pump secondary circuit failure. The EEC senses infinite resistance to ground from the fuel pump on the Fuel Pump Monitor circuit.

codes 22 and 95 im not to worried about because that probably was cause when i was changing the map sensor and when the fuel pump was staying on.

im not sure if the canister purge solenoid circuit is the problem here but if im wrong tell me. any help on what i should do about this evp sensor and circuit failure would be greatly appreciated. thanks

 

Just a little help to keep you from straying off on the wrong path...
I bought my truck from some random guy at craigslist and what i didn't know was that there was no oxygen sensor. Took me a while to figure out why i was getting such crappy mpg but when I got around to looking for it I found a bolt in place of the oxygen sensor. Long story short, my truck (93 f150 5.0L) ran great without it before and the only noticeable effect now of having the O2 sensor is better mpg. Could be a black magic O2 sensor problem for you but for me, not having one barely affected my truck.