mat_fab_tx

Alright, I got a 95 F150 4.9. its got a crate motor (4.9) new trans. Truck has been running great but it was time to do some maintenance. changed the plugs (OE), new injectors. running great. well the rear tank never worked so I finally broke down and bought a new tank and a new fuel pump assembly. now all the sudden truck is bouncing around at idle and dying. mind you I have not even used the rear tank yet. so thought mabey its the fuel canister purge valve. changed it, no difference. changed the 02sensor, no difference. fuel pressure regulator, no difference. The front fuel tank pump was replaced around 25k miles ago. (when crate motor was installed). So I went ahead and put a couple gallons in the rear tank to see if the brand new pump would run right. It ran better, but still not great, truck is smoking and sputtering still. anyone dealt with this issue before? I have no idea where to go from here... any help would be appreciated.
P.S, I was going to test the fuel pressure but the tool I rented was missing the adaptor fitting so wasn't able to check it. But I don't feel like that is my issue since the rear pump is brand new and it's still not running right.

memoniz

Need to check your fuel pressure. Get the adaptor. Should be between 45 to 60 lbs. Also might want to check your fuel filter. May have jarred something loose switching things out and clogging the filter.

Shagg

What color is the smoke that is coming out of the truck? And did you test any of those parts before replacing them? You should still check for proper fuel pressure, New =/= good when it comes to parts, I learned that the hard way a handful of years ago. The still-functioning factory parts are better quality than pretty much any of the modern replacements in the vast majority of cases.

Steve83

You should put ALL the truck's details & history (as much as you know) into your signature so it shows with each post, as this page explains:

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Phone apps don't always show signatures, so you may need to switch to a real browser in desktop mode on your phone, or just use a desktop/laptop computer. Put your location (nearest city) in your profile & upload an avatar of the truck. The more pics you post (NOT in your sig) of the truck, engine, wiring, labels, & undercarriage, the more likely we can help you. Not all its details are relevant to these issues, but you don't necessarily know which ones are relevant, so just put everything in now.Injectors are NOT maintenance parts. Maintenance is ONLY what's listed on the published schedule (which is nearly the same for all these trucks).

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This is all semantic, but OE means "original equipment" which means the actual parts installed on the assembly line. All OE plugs are worn out by now. OEM means the company ("Manufacturer") who supplied the assembly line parts to Ford, but since plugs don't carry the manufacturer's brand, and since the actual supplier for most parts has changed several times in the past ~30 years, there's no telling who was the OEM for your truck's OE plugs, or if that company is still in-business OR making plugs for these trucks, OR who makes the current supply of Ford/MC-branded plugs for your application. So you might have installed new Ford/MC plugs, but probably not OEM, and certainly not OE.What brand/PN/source, for each part? Did you personally do the work, or did you pay someone to DIFY?Why? Did you do some diagnosis that indicated a CANP fault?Why? What test did it fail? Changed it TO what (brand/PN/source)? Did the replacement pass the same test the previous one failed? Did you keep the previous one? I'd put it back on.Why? What test did it fail? Changed it TO what (brand/PN/source)? Did the replacement pass the same test the previous one failed? Did you keep the previous one? I'd put it back on.Why? What test did it fail? Changed it TO what (brand/PN/source)? Did the replacement pass the same test the previous one failed? Did you keep the previous one? I'd put it back on.

Seeing a pattern? Throwing part$ at a problem is NOT diagnosis or repair. The more you disturb on an antique vehicle, the more problems you're likely to create.Why? ...That's the best idea you've posted. Ignore your feelings - you can't feel what's wrong with a vehicle. Diagnose it logically. If you plan to keep & drive this truck, you should start collecting the tools & equipment that you're likely to need frequently, and a fuel pressure gauge is a good investment. This is what I use (professionally), but there are decent ones in the $40 range.