Hey all- inherited a 1991 f150 4x2, 4.9 i6..
sat for two years before I received it, so naturally I assumed there'd be some issues from sitting.

did an oil change, coolant flush, changed fuel filter, sprayed some cleaner in tb, ran whatever super fuel treatment injector cleaner stuff in both tanks along with midgrade gas..

got a new battery too.

I've never driven a domestic until getting the truck... fell in love immediately and loved doing all of the above with no walkthroughs as I have to use on my subaru..

i do have some issues though, and again since I know nothing about domestics I'll start at the beginning.. truck starts up fine in any weather generally, but sometimes it doesnt want to restart (like an hour after I turned it off).. one or two tries does it and it'll stay on and sound perfect..no tach but is revving higher for the first 30 seconds it turns on and sounds good, then slows down a ton (doesnt warm up in that 30 seconds or anything).. but yes..slows down a lot and becomes much more quiet.

upon throwing it in any motion gear it sounds like it aches to have been dealt load and when i go to hit the gas pedal a lot of the time it shudders.. not always though which is the perplexing thing. Drove it through 20 stoplights with no issues but then the second I hit arby's drivethru it started acting up. pretty scary trying to make distance calls in traffic not knowing if youll get going fast enough quick enough.

ready to replace spark plugs (do I have to take off manifold to access these on 4.9?? looks tight) hoping thatll help.. i dont know what the power level is sposed to be - she's sluggish but gets up to speed if i mash pedal. grinds (pings i spose) up hill if i try to keep her maintaining 55 or 65 for instance.

only obvious thing i see is huge split in exhaust as it goes over rear axle.. noticed that this morning as a nice cloud was coming from under the bed..

^does this matter on domestics? backpressure and yadaya or what.. tips?

sorry, this is a huge post - internet's failing me though, can't find the website for 4.9v6 enthusiasts or whatever.

Appreciate it guys, this truck as is seems to be pulling me further and further away from my 05 300hp/tq legacy gt

 

What's the mileage on the truck?

As long as the split is after the cat-cons, you should be fine. If it's after the muffler, it's no need for concern as long as fumes aren't making their way into the cab.

Isn't it nice not to need a shop manual to flush coolant?


When it won't restart, does that mean it won't crank, or cranks but won't fire? It's somewhat common on old trucks to get corroded grounds, which causes the starting relay (little black thing just back from the battery) to fail.

Domestic cars run at a very fast idle when first started, moreso in cold weather (out 07 Explorer idles at 2000 for about 30 seconds, then drops to 1000, then settles down to about 600, it's normal idle. My truck with the 5.8L idles around 1500 in cold weather, about 800 normally.

If you've got a break/split in the exhaust, the motor can sound faster than it is. I had a similar truck to yours but a 93, and the exhaust was gone after the cat/cons. What later proved to be just over 2000 RPM sounded like 4000 in my current truck. Might want to install a tach, not expensive and it's not hard to do on these motors.

Shouldn't need to remove the manifold to change the plugs...gotta stop thinking in terms of space-cramped import motors.

For trans shuddering. First, check the door sticker to get the code in the "trans" box, and compare it to the thread in the transmission forum. It's likely to be either the AOD (automatic overdrive, vacuum actuated), or the E4OD (electronic 4 speed overdrive). Either way, you'll probably want to do a pan-off fluid/filter change at the least. Not hard, undo bolt pans, it falls off, dump fluid and refill.

The 300 is not a legacy motor. It's 160hp with about 200ft/lbs of torque. On an automatic, it is rather sluggish (much better mated to a stick). Don't expect to be raping Corvettes off the stoplight.

 

Ah I appreciate the reply and apologize for such a jumbled first post-

87k on original everything to my knowledge

got spark plugs and wires changed in about 30 minutes, not as troublesome as I thought.

seems to run a lot meaner now - when I give her some gas it sounds good and doesn't near die after I let off the gas. also when i put the truck in gear (d or r) it starts to move on its own, before it'd just sit there..presumedly too weak to inch in any direction?

re the no restart thing - its like I turn it on and it sounds like everythings poppin' under its own power so i let off the key and..nope, dies and dash lights come on

odd you mention the tranny - the gear selector no longer lines up well (in D only half of D is orange, infact I drove a few miles in 2 because it looked like it was in D.. realized before I took her out on the interstate thankfully). I notice if I'm coasting to a near hault and hit gas it doesn't EVER shudder.. but most times after sitting for a second at a complete stop (like a stopsign) then try to go, it bucks and sounds like its gonna kill the motor. i'll plot out fluid change tomorrow if it isn't too chilly


glad to hear re the exhaust! seems like im in the clear with everything but the possible trans shudder.. and oh yea, the doors don't lock - I looked for the fuse but its an odd one, metal covered so I cant see if its fried.. figured i could atleast still turn key in door to lock it but nope..

ive read of door lock actuators and this and that - but could this magical metal covered fuse be the problem? its like wheni twist the key in the lock it feels jammed.. cant push down or pull up on the lock pin either from inside. may be noobiest question of all but i'd love to get her lockable before I tote any valuables with me.

thanks for the help rawarrior - so excited to have a near reliable vehicle. I'll leave the (insert typically fast car here) stomping for the legacy i've just always wanted a truck and, as a big guy, feel a lot better crusing around a bit elevated.

 

If the door lock is jammed, as in the key won't lock/unlock it, then something's wrong with the actual mechanism, and the fuse likely popped when the actuator tried to move the jammed rod. Take the door panel off whichever side the key doesn't work in, remove the plastic sheet and get a flashlight. Follow the little knobby that down the panel until you find the lock assembly. Try to turn it by hand. If it still won't move then the lock is either toast or a piece 'o crap is jammed in the key slot and clogging up the works. Also, check to see the actuator is securely bolted to the door (it's way down there, use flashlight). On the rear-facing side of the door panel, about 2-3" from the bottom should be one hexhead bolt, that's holding the power lock actuator. If it's loose or gone then the actuator just pulls itself up and down, instead of the lock lever.

Also, check all the wires for the driver side "control panel" in the door. There's a bunch of wires with funny little slip connectors that go into it, ensure they are all firmly inserted. They can be not connected, but still appear to be in the slot, and if one is missing, the whole power lock thing doesn't work.

A blown fuse would not interfere with manual lock operation. On these trucks a square head key operates the ignition and door locks, they are keyed alike from the factory, an oval head opens the glovebox and nothing else. If the locks were changed by the PO then the key may simply not fit them.

For the gear selector...just do it by feel. Pull it 3 "notches" from park for D, don't worry about the orange needle. However if the shifter has a lot of play in it, or feels very loose then the cable may be bad and when those go it's very, very inconvenient.

Also a little tip for Fords...when you put the selector in 2, it goes to second gear ONLY and stays there at any speed. Some other American brands and all imports take a selection of 2 to mean "use first and second gear". Drive uses all 4 gears, the O/D button locks out 4th and uses the first three normally. But the 1/2 selections lock it into that gear. My truck with the E4OD does this, and our new Explorer does too so I assume it's a Ford thing. Our old Jeep didn't though.

 

Thanks again, you've been a huge help.

Thinkin the round head key fit in the lock but wouldnt turn it, and the square head didnt fit at all - i'll take off door panels today and get to the bottom of it.

Currently conducting tests to see what my gas milage is looking like (can't be good, reading about a half a tank after a ~40 mile trip...was full prior to.)

I know gas guages cant be but so accurate, front tank doesnt even register as having anything in it.. just want one working tank and gauge and i'm set. I also noticed last night in my driving that if I let my foot off the brake and then wait say five seconds and hit gas it wont do the studder at all.

Fun day ahead of me it seems

Er in thinking about my gas milage and reflecting, reading some posts...
being as this is my first domestic I kind of..expected the smell of gas and yadaya...
but really, last night I rolled down the window and noticed how relieved I was to smell fresh air-
something stinks driving this truck, it's not an egg smell, more like gas/exhaust. When its cold I don't see any sign of exhaust leaks anywhere but after rear axle so i'm sure its not leaking somewhere straight to cabin, moreso assuming I'm running rich?

In changing plugs cyl1+2 were oil'd, rest back were whitish.