351w missing
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Junior Member
Joined: Dec 2015
Posts: 7
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351w missing
Hey guys, so I gotta 95 f250 xl 351 5.8l that's missing bad. It has 370k on it, it started out only missing under load like when I was hitting the gas hard and now it's missing so bad sometimes it will barely move. I know a little about cars but it's been a while since I've been able to work on them I'm a little rusty lol.
But it started out when I got the truck ever so often it would bog down and act like it was running out of gas. I could hit the tank switch a few times (it has no front tank) and it would clear it up but I let a friend borrow it to haul some wood and he hit a stump and crushed the exhaust so I had to cut it off at the back of the cab it doesn't have cats it came like that. But I drove it for about a month and it started ro slowly get worse and worse. I would have to do the tank switch thing more often but one day after it sitting for 3 days I came out to start it and it wouldn't start. It acted like it wasn't getting fire or out of gas. I had to hold the pedal to the floor for a very long time before it even tried to start and after it finally started it was idling fine but when I hit the gas it missed real bad but I could barely hit the gas and it wouldn't miss only when I hit it hard. Then slowly over time it got worse and worse and now I have to hold the pedal to the floor to start ut when it's cold when it's warm it starts fine but it even misses at idle now and will barely move. Oh idk this may have something to do with it but the mpg is absolutely horrible I mean I really think it's like maybe 2 or 3 mpg I can literally watch the gauge go down.
I don't really know how to diagnose it as none of the stories or questions I've seen are like this. I'm hoping it'd not to far gone where I have ro get rid of it it has a bunch of new parts on it but like I said it has almost 400k miles leaks oil leaks gas lol. Should I even worry with it I have 3 other cars but it's my only truck I've had since I was 18 and 32 now lol.
But it started out when I got the truck ever so often it would bog down and act like it was running out of gas. I could hit the tank switch a few times (it has no front tank) and it would clear it up but I let a friend borrow it to haul some wood and he hit a stump and crushed the exhaust so I had to cut it off at the back of the cab it doesn't have cats it came like that. But I drove it for about a month and it started ro slowly get worse and worse. I would have to do the tank switch thing more often but one day after it sitting for 3 days I came out to start it and it wouldn't start. It acted like it wasn't getting fire or out of gas. I had to hold the pedal to the floor for a very long time before it even tried to start and after it finally started it was idling fine but when I hit the gas it missed real bad but I could barely hit the gas and it wouldn't miss only when I hit it hard. Then slowly over time it got worse and worse and now I have to hold the pedal to the floor to start ut when it's cold when it's warm it starts fine but it even misses at idle now and will barely move. Oh idk this may have something to do with it but the mpg is absolutely horrible I mean I really think it's like maybe 2 or 3 mpg I can literally watch the gauge go down.
I don't really know how to diagnose it as none of the stories or questions I've seen are like this. I'm hoping it'd not to far gone where I have ro get rid of it it has a bunch of new parts on it but like I said it has almost 400k miles leaks oil leaks gas lol. Should I even worry with it I have 3 other cars but it's my only truck I've had since I was 18 and 32 now lol.
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Joined: Jul 2007
Posts: 3,805
Likes: 480
From: Cape Girardeau MO
Suggest to get the codes pulled, to see whether the computer has flagged anything which may shed light on which direction to go.
FWIW, some vehicles cut off the fuel when cranking with the accelerator to the floor - a flooded-clearing feature. Not sure if this vintage does that, though.
Suggest to check your fuel pressure at the Schrader valve on the intake fuel rail, also inspect the fuel pressure regulator looking for a failed diaphragm letting fuel back through the vacuum line.
This vintage wasn't any kind of fuel economy wizard, but would expect somewheres at least in the 10mpg range rather than what you report.
May check the timing, if nothing else to scratch that off the list of possibilities. Also, be sure to remove the SPOUT connector when checking, and make sure it's seated back properly when done.
Not knowing the history of the engine, would expect the timing chain has a bit of stretch after that many miles - don't think it's a root cause of your current problems but may interfere with getting things dialed back to spot-on perfect, since the valve train is expected to be running a bit 'late'.
Agree with user Apple - at least have a look at the air filter, cap, rotor, wires, and sample a few plugs to assess their conditions.
Could get into the more obscure things, like the pickup screen in the tank is clogged or fuel pump weak - but those and the fuel filter should show up in fuel pressure trends, such as when holding your foot on the brake while in gear and loading the engine up a bit to call for more fuel than at idle. Another is a very weak coil, but there are resistance specs for it and for plug wires so to avoid blindly shotgunning parts.
FWIW, some vehicles cut off the fuel when cranking with the accelerator to the floor - a flooded-clearing feature. Not sure if this vintage does that, though.
Suggest to check your fuel pressure at the Schrader valve on the intake fuel rail, also inspect the fuel pressure regulator looking for a failed diaphragm letting fuel back through the vacuum line.
This vintage wasn't any kind of fuel economy wizard, but would expect somewheres at least in the 10mpg range rather than what you report.
May check the timing, if nothing else to scratch that off the list of possibilities. Also, be sure to remove the SPOUT connector when checking, and make sure it's seated back properly when done.
Not knowing the history of the engine, would expect the timing chain has a bit of stretch after that many miles - don't think it's a root cause of your current problems but may interfere with getting things dialed back to spot-on perfect, since the valve train is expected to be running a bit 'late'.
Agree with user Apple - at least have a look at the air filter, cap, rotor, wires, and sample a few plugs to assess their conditions.
Could get into the more obscure things, like the pickup screen in the tank is clogged or fuel pump weak - but those and the fuel filter should show up in fuel pressure trends, such as when holding your foot on the brake while in gear and loading the engine up a bit to call for more fuel than at idle. Another is a very weak coil, but there are resistance specs for it and for plug wires so to avoid blindly shotgunning parts.
Thread Starter
Junior Member
Joined: Dec 2015
Posts: 7
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Suggest to get the codes pulled, to see whether the computer has flagged anything which may shed light on which direction to go.
FWIW, some vehicles cut off the fuel when cranking with the accelerator to the floor - a flooded-clearing feature. Not sure if this vintage does that, though.
Suggest to check your fuel pressure at the Schrader valve on the intake fuel rail, also inspect the fuel pressure regulator looking for a failed diaphragm letting fuel back through the vacuum line.
This vintage wasn't any kind of fuel economy wizard, but would expect somewheres at least in the 10mpg range rather than what you report.
May check the timing, if nothing else to scratch that off the list of possibilities. Also, be sure to remove the SPOUT connector when checking, and make sure it's seated back properly when done.
Not knowing the history of the engine, would expect the timing chain has a bit of stretch after that many miles - don't think it's a root cause of your current problems but may interfere with getting things dialed back to spot-on perfect, since the valve train is expected to be running a bit 'late'.
Agree with user Apple - at least have a look at the air filter, cap, rotor, wires, and sample a few plugs to assess their conditions.
Could get into the more obscure things, like the pickup screen in the tank is clogged or fuel pump weak - but those and the fuel filter should show up in fuel pressure trends, such as when holding your foot on the brake while in gear and loading the engine up a bit to call for more fuel than at idle. Another is a very weak coil, but there are resistance specs for it and for plug wires so to avoid blindly shotgunning parts.
FWIW, some vehicles cut off the fuel when cranking with the accelerator to the floor - a flooded-clearing feature. Not sure if this vintage does that, though.
Suggest to check your fuel pressure at the Schrader valve on the intake fuel rail, also inspect the fuel pressure regulator looking for a failed diaphragm letting fuel back through the vacuum line.
This vintage wasn't any kind of fuel economy wizard, but would expect somewheres at least in the 10mpg range rather than what you report.
May check the timing, if nothing else to scratch that off the list of possibilities. Also, be sure to remove the SPOUT connector when checking, and make sure it's seated back properly when done.
Not knowing the history of the engine, would expect the timing chain has a bit of stretch after that many miles - don't think it's a root cause of your current problems but may interfere with getting things dialed back to spot-on perfect, since the valve train is expected to be running a bit 'late'.
Agree with user Apple - at least have a look at the air filter, cap, rotor, wires, and sample a few plugs to assess their conditions.
Could get into the more obscure things, like the pickup screen in the tank is clogged or fuel pump weak - but those and the fuel filter should show up in fuel pressure trends, such as when holding your foot on the brake while in gear and loading the engine up a bit to call for more fuel than at idle. Another is a very weak coil, but there are resistance specs for it and for plug wires so to avoid blindly shotgunning parts.
Ok thank both of you I'm off today and finally have some time to myself so now I have at least a starting point and a list to check off. I really don't wanna get rid of er she's gave me a good 150k she's worked her butt off so felt bad just scraping it. Plus I have a hard time scraping even non running cars unless they are totaled. Sorry I'm rambling again lol I'd I have any more questions or need some advice I'll be back and I'll let you guys know of it's worked or not.
Senior Member
Joined: Oct 2016
Posts: 3,700
Likes: 766
From: Parts Unknown
With that many miles, I would want to know where the compression is at before spending money on parts.. Low or uneven compression, the engine might never run the right way no matter what you do to it..