Richard Warick

I have a 1995 f 150 with a 4.9 and a 5 speed stick. it starts fine and then starts to shake,the hotter it gets the worse it runs, it pops and smells rich of gas. i gave it a full tune up and changed the gas filter, and cleaned the throttle body. thought it was the cat and removed the exhaust . i noticed if i re move a vacuum line from the engine it runs better. i cant find the maf or the map censer . I am at a loss . any idea what i should do next , any help will do . Thank you Richie

Ford2581

On the fuel pressure regulator there is a vacuum line, unplug it and smell or look for gas contamination, if its leaking into the vacuum line replace it.
The MAP sensor is on the air box for the A/C Heater, the MAF sensor is on the air ducts between the air filter and throttle body.

Richard Warick

i checked the vac line for the fuel pressure reg and no gas , vac was good from the line.i still cant find the maf, did find the map not sure how to see if it is good, removed the vac line from the map and eng run faster.not sure what to do next.

Ford2581

If it's a 1995 the MAF sensor should be inside a metal housing right next to the air filter housing, earlier trucks did not have a MAF sensor. Since it happens when it gets hot it's probably a feedback sensor when it goes into closed loop. I've seen O2 sensors do that.

Richard Warick

ok here we go i want to tell the whole story from the beginning , so maybe you have a better idea what to do. 3 days after i bought the truck i took gas from the rear tank and put it in the front tank, because the org owner told me there was good gas in there, but rear tank didn't work and has not worked for a couple of years, also put some in from another truck i had. over filled it with the gas can. poured out 2 times.also i think the gas was bad. then about a day later the first thing in the morning it started but shook and back fired and bucked and had no power worse when it got hot. ok saying all that, i took the rear tank out of my other truck and put it in this one . pump was good and tank was clean. i filled it with 12 gals good gas and added some sea foam. changed gas filter and gave the truck a full tune up.and it still did the same thing. coming back from the gas station i looked under the truck and the cat was glowing, i thought i found the problem a clogged cat so i removed it. still the same problem, last thing i did was clean the throttle body and check the vac line to the fuel regulator. ok so now you know the whole story. whats my next move?

Ford2581

The bad fuel changes everything, I would completely drain both tanks, replace the fuel filter. Fill the good tank with a fresh tank of gas (not adding new gas to potentially bad gas) and hope you did not clog up the injectors with the old bad fuel.
The cat was probably glowing from running like crap and missfiring and possibly melted it.

Richard Warick

I did train the back tank completely put fresh gas and sea foam and change the fuel filter and only ran the back tank and it still does not run right

Richard Warick

Also I figured if it was bad injectors it wouldn't run right right from the start it runs decent when I first started and then the warmer it gets the worse it gets but it does run good for about 12 seconds and then it starts to go to hell

RLXXI

The coolant temp sensor could be bad, I've seen them go full cold -40* making the pcm think it needs to richen the mixture, check the connector and make sure the terminals aren't discolored or spread apart. Also put a fuel pressure gauge on it, I've seen those go full open and peg the pressure to 100 psi, when that happens the injectors can't hold it back and dump raw fuel in massive amounts into the engine.

Richard Warick

not sure what to check next, money is a big issue , any ideas would be great and Thank you , for your time