95 5.0 sounds like its missing [Mostly Resolved]
 

1995 5.0L 4r70w.
Sounds like its missing, chugs when driving.

Replaced fuel filter, plugs, wires, Dist cap and rotor button. Rebuilt a stuck EGR , seafoamed the intake and cleaned MAF. Nothing changed. Checked fuel pressure 31psi running, 38psi KOEO. Checked compression #4-120psi, #5-130, #8-135, rest were 125. Found a few broken vacuum lines and repaired them. Trying to check timing but old Heathkit timing light isn't bright enough to see the marks.

Engine codes, 10, 536, 538, 632.

Check engine light not on while idle or driving which bothers me because it ran great when the light was on.

Got a new timing light and made marks with a sharpie so I could see them easier. With the Spout jumper out it show about 8 maybe 9 BTC. I think 10 BTC is recommended but have heard lots of people say 12 BTC on 5.0's.
I will adjust it a bit.

Adjusted timing to 12 BTC and didn't notice any difference so I adjusted it back to 10 BTC.

Really scratching my head on this.

You can safely advance it until you get spark knock, then back it off a couple degrees, don't go past 16.

I'd suspect dirty injectors - throw some Techron in the gas and see if it improves.

Disconnect the battery for 20 minutes and see if any codes return.

Another possibility - you may have 31 psi fuel pressure with the engine running (which does sound a bit low), but what about under load? You may have a bad FPR.

I was looking at this post last night... I was thinking 31 psi fuel with it running was a *little* low as glc pointed out. glc might be on to something.

I did put seafoam in the front tank but it will probably require more than just one can. I will also check out the fuel pressure regulator.
Thank you for the responses, I will update soon.

No, do not use Seafoam, use Techron. Seafoam is worthless except in old carbureted engines.

I'll try and find some Techron.

Walmart sells it as do all parts stores.

https://www.walmart.com/ip/Techron-C...2-OZ/407614589

I had an 85 F150 5.0 that I bought new, and it would pick up a miss sometimes, but fuel injector cleaner stopped it everytime.

I used to use BG44k in my 4.2l's when it started ping (carbon buildup). But they quit making BG44k (or I can't find it). Even my local Ford dealer used to throw me a free can now and then if I asked really nice. The SM would go get it from the parts dept.

Now I use Techron when it occurs, and it's like magic. Every 5-10k does the trick.

So I don't really need the BG44k now that the Techron seems to me a viable alternative.

Today I put 20oz of Techron in the rear tank and swapped the fuel pressure regulator. I drove it about 10 miles down the backroads and then took the highway back home. It seems to run better but still boggs down under load. I also noticed that when it boggs down, my fuel gauge goes way past F. As it starts picking back up and running smoother, the Fuel gauge goes back to normal. This has me thinking that perhaps the fuel tank switch is dirty and needs replacing.

They still make BG44K but it's not the same since the reformulation to meet VOC standards. It's also very overpriced.

Is it possible that a bad contact in the tank selector switch can cause low voltage or current to the fuel pump?

Getting ready to post something almost like this but I have the 95 5.8 ... and still have not found my problem . 32psi @ idle and jumps to 42 if I pull vac hose off regulator.
Have you checked your TPS sensor ? Thought I found m problem. Voltage was good at idle but as throttle opened voltage dropped . I replaced it but it did not help. I am assuming your have the same problem on both tanks ?