Here we go 1995 f250 with a 5.8 truck was running fine iv had a check engine light on for o2 sensor since iv owned it so a year now, just replaced it yesterday along with a vss sensor and header gaskets I dont know if it's related to the o2 but now it seems to have a hesitation If step on it hard and it feels sluggish no codes just feels off it use to drop a gear and goooooo

About 1800 miles ago I did the following
motor craft spark plugs
Spark plug wires
tps
iac
cap and rotor
blocked off egr
fuel filter
fuel pump

What do you guys think

 

Have you checked the timing?

 

This is the a sudden issue I set the timing at 12° six months ago with a new dizzy due to bad pick up

 

1800 miles ain't much but tomorrow I'm going to grab a msd cap and rotor with brass terminals and maybe a nice set of accel wires and see how that works I used the house brand Wires before maybe my headers have messed with the boots? I'm going to buy the heat stuff to put around the ends to

 

With all that work replacing parts/tune up, you may have broken a vaccuum line. Check those first, almost free fix.

 

Make absolutely sure the 02 sensor is plugged all the way together at the connection. Don't ask how I know

 

if you don't find any vac leaks, check fuel pressure. it doesn't sound like fuel pressure is insufficient, as you would experience more than hesitation down low. although perhaps a clogged filter could cause your woes.


keep pulling codes too, something might pop up.

 

Might ought to clean your MAF (Mass Air Flow) sensor if your truck has one. That can cause similar symptoms. Get a set of "tamper proof" Torx bits (the ones with the hole in the middle) and take the 2 screws off the sensor. Pull it straight up and out and clean the little wires off with some electronics cleaner. Be careful cause they're real fine wires wrapped on ceramic insulators, you don't wanna damage them.

 

My truck is not a maf it's speed density. I'm going to check fuel pressure I listened to the pump today and it seems real loud. Also as the truck is running I here what sounds like a spark plug wire arcing out but none of them are iv looked at them in the dark and true spraying them with water nada it sounds like it coming from driver side rearish

 

I have 45psi at the rail at idle. And not as of today I have new msd cap and rotor and accel wires and the truck seems to be about the same but worse anything past half throttle and it just bogs down but if I go into it slow it's OK seems to miss at idle every now and then to just a little

 

I did find my dizzy clamp lose a bit tightened it could this be a timing issue would the bog mean to far advanced or retarded

 

That is too high for a V8. Should be 30-32 PSI at idle.

 

45psi at idle would be OK if vacuum is removed from the regulator, with vacuum it should be 30-35psi.

I suggest you check the air tube at the back of the motor for leaks, it's part of the smog system and is attached to the exhaust via ports in the back of the heads. Any air leak here or anywhere else upstream of the O2 sensor will cause a severe lean condition which will show up as a heavy stumble and power loss.

 

Update I found a lot of powder and metal shaveings in my dizzy so I replaced it runs a bit better I think my timing is a tad advanced it misses at idle a bit and going down the road and chugged a bit starting once my fuel pressure is at 31psi at idle and with vaccume off its at 35-38 psi I used a better gauge this time my other one didn't quiet fit to we'll on the shader valve

 

Bump bump ?..