tailgatefisher

Great coming back to the Forums...Life has been busy!

My 91 4.9 inline has been sucking gas and alittle down on performance. I removed my dist cap and had alittle carbon build up on the button and contacts that I cleaned off with some fine grit sand paper, helped alittle bit on the power side but fuel performance is still draining the pockets.
I have a tendency to let my tank drain down around an 1/8 before adding more fuel and am wondering if I may have fouled up my fuel filter by doing so. This would be a easy repair if so. I have no idea what changes to expect running with a dirty filter. Does hesitate alittle when punching the gas.

Changed my air filter
Plugs and wires are gapped and fine
No vac leaks
Pulleys not dragging
Cleaned out everything with seafoam
No misfires

Only two things that a can think of is the fuel filter or possibly the engine temp sensor has gone bad and the computer has me running in open loop. My temp guage does flux up and down while driving and the guage needle never really goes pass the "N" in normal. My thermostat opens up as it should, I Have held the hose and felt the pressure surge of coolant when it opens. The guage needle shouldnt really go downward after the thermostat is open if Im correct?

I have a hard time spending the money on a mechanic to do a over all tune-up when we all know that corners are cut at times with coffee breaks and a smoke. Afraid to get a bill and find no difference at all in performance and fuel economy.

Any Idea if Im heading in the right direction with this?

94Bronc

when the therm. opens i'd expect the temp to drop slightly. maybe its just not enough to notice though on your truck. mine sits at or below the n religiously and i think my therm. is stuck open. fuel filter replacements can do amazing things with mileage and performance, whens the last time it was replaced? unless you have a rusty gas tank running down to 1/8 isnt all that bad, the only "bad gas" you'll get these days is from what you eat...

dirtcrew51m

Thats because the crack smoking brain dead politicians who think global warming is real is making gas companies put 10% methanol in gas. Result: loss of mileage and power. Most vehicles can not compensate for the more fuel needed to burn the percentage of methanol that is blended with the gas, thus the computer cant tell that the engine needs more fuel to operate efficiently.

tailgatefisher

You hit the nail on the head dirtcrew. This is also a major factor im sure. I noticed a change in my truck with the 10% Eth. Actually with our Explorer also.
My fuel milage droped like 3 mpg. 1 mpg due to the eth factor.

I am gonna swap out the fuel filter some time next weekend depending on time and possibly pull my thermostat and check the timing.

Havent ran codes on my truck in almost a year, I guess that will be my first on the to do list!

Anyone one else have a suggestion?

BiggestFordFan

Yeah it sounds like your running lean, if it hesitates to go when you hit that gas. so it might be a dirty fuel filter

dirtcrew51m

Lean is from the methanol. Probably why it hesitates a bit.

Buddhaman

when was the last time you changed your o2 sensor?

BiggestFordFan

That does make sence! So when was that inaffect? Because this summer I got 12 mpg and I drove more aggressively but now I've been driving with slower acceleration and I get an avg of 10 mpg

dirtcrew51m

The tards oops I mean the gmen start around sep\oct for the winter season.

tailgatefisher

Havent checked my O2 sensor, when I run codes on my truck this weekend the O2 should probably throw a code if its bad.

Found that when I burn 87 octain my power decreases but when I use 89 it increases back up to the way it was before the 10% eth.
Figure 87 octain minus the 10% of it being eth would make it now 85 octain due to the 10% displacement; 89 minus the 10% is now more like 87.
Now I guess we are forced to pay the higher cost of fuel from our Goverment inorder to keep our older non-hybrid automobiles running up to par. Just a wild thought to throw out there.