Lack power at 60-75mph or trying to pass

[sbany62]

Hello everyone Steven here been a wheeler most of my life just love being outdoors . So I have 1989 bronco XLT ,351 and have replaced booth fuel pumps and regulaterand filter when starting to excelarateno problem tili get to 60to 70mph starts to starve for gas , I have tested flow and seems fine installed pressure gauge and it was at 38to 41 lbs while driving so I decided to change filter again note tank had no rust very clean but when draining filter into glass jar black soot came out of filter ,stock plastic lines and changed filter again after 500.00 miles and not as much but still getting black soot out of filter,I do run seafoamevery couple of months but didn't think that would be the source even when pulling steep grades lacks file /power any help you can through my way I'd appreciate Steve loyal Ford man For ,Our Recreational Demands.

 

[Rons beast]

Hey Steven, Welcome.

You problem may not be fuel related.

Did the problem just start, or happen after replacing the fuel pumps?

Do you know what the timing is?

Have you tried gas from a different source (station) ?

Can you verify the trans is shifting properly? 

 

[sbany62]

At first I thought it was a bad pump replaced both kinda started at ruffly same timeing is at 10 had to replace (just did two weeks ago )vacuumed modulator but trans works good I thought it could be in throt.posit sensor, or mass flow intake sensor but I'm scratching my head tryin to find what's wrong

 

[miesk5]

yo Steven,

WELCOME!

As Ron advised.

Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-co...&mode=threaded

A helper is good to assist in reading Codes; best is to take a cell fone vid and replay it.

Some basics;

Visual Check

Battery is fully charged & connectors and grounds are clean

Inspect the air cleaner and inlet ducting.

Check all engine AND HVAC (under hood & in /under dash) Vacuum hoses for damage, leaks, cracks, blockage, proper routing, etc.

http://broncozone.com/topic/14269-code-reader/?pid=74587&mode=threaded

Fuel Filters cost a bit, but exc. for a tank flush and seal, it may be only choice.

Normal Engine Vacuum at Idle should be 15-22 in-HG

If not stardy see this chart by Ford http://www.diesel-dave.com/vehic/manual/stj/stj30013.htm#extract_334

vacuum modulator- ensure there is vacuum there w/eng running; ipull vac line off. any trans fluid in line means diaprharm is bad.