I just bought a 1997 f150 xlt with a 4.6 i noticed when buying it that it had a miss at idle so i took it for a drive and still misses while driving (Viberating) while driving , he said it was bad gas he took it to a mechanic they cleaned something out and added 30$ in fuel and told him to top it up with high test fuel when he gets home and all will be well , so he told me that he didnt top it up but it is a bad gas issue , so i drove it home and added 10 in fuel to it , still ran ruff , so i changed fuel filter and it had some red rusty gas come out of the end of filter so i put new filter on and then started it and it then blew white smoke out exaust and dripped some oil out exhaust , so i was told it was a clogged injector , so i took them all out and cleaned them out with some cleaner stuff from gm and blew them out i repeated it a few times then reinstalled the injectors , that cured the white smoke out the exhaust and the oil dripping , but still runs with a miss , has a lack in power aswell when driving it , anyone got any ideas?? would help alot , think it is a costly repair ??

 

Have you scanned the OBD for codes?

The ignition system needs to be gone through (spark plugs, wires, coil packs) and possibly a compression test. Dripping oil out the exhaust is NOT a good sign.

 

the oil is not dripping anymore once i cleaned the injectors out and reinstalled them it didnt do it anymore a mechanic told me it was doing that because the injector was stuck and the oil was washing the walls or something it aint doing that now i cleanned them just still has a miss too it , i have to get it scanned can i take it some place and get it scanned and that is it or ?? i also heard ford f150 does not like champion plugs would that be an issue as well it has champion plugs in it

 

X2 on the compression test. My 5.4 ran rough when I bought it (and I knew it) - I figured it just needed a tune up, but my dad had suggested that I run a compression check, I found 1 cylinder that was only making 60PSI, another was only making 120PSi, should be up around 150-175 on these motors (someone please correct me if I am wrong)

You can take the truck to get scanned at your local parts store, around here in RI, Autozone and Advance will pull codes from the computer free of charge. Once you are given the code, if there is one or several, you need to look up what it means and that will give you a direction to go in. I believe there is a DTC (Diagnostic Trouble Code) list on the forums here.

As far as plugs go, from what I have learned (here, in other forums, and from other Ford enthusiasts) only run Motorcraft plugs.


-Alex

 

Champion plugs are crap in that engine. So are generic plug wires.

Change your oil, use only 5W20 or 5W30, and use a Motorcraft, Purolator, or Wix filter. If you have fuel in the oil you need to get it out of there.

 

get it scanned, see which plug is missfiring or plugs, then buy new plug wires and sparkplugs, good wires and sparkplugs, not crappy ones, if that doesnt fix it see if one of the back two heater core houses are leaking into your sparkplug hole, that is what happened to mine that caused it to missfire

 

Are you getting a check engine light?


One common problems with these 4.6's is the throttle body ports will, over time, clog up with carbon. It requires you to pull off the intake and top part of the throttle body (where the butterfly valve is located) and, using a toothbrush and cotton swabs and lots of intake cleaner, clean all of that carbon out of your intake. I've done it 4 times on my 4.6 and it always makes a big difference. Takes 2-3 hours and regular tools (ratchets, screwdrivers,etc). Nothing too complicated.

Do a search for intake cleaning, throttle body cleaning, etc and you'll find that it's an issue with every 4.6. If you just bought this truck, chances are it hasn't been done properly to your truck.

 

As an owner of one of these trucks, the advice above is spot on. For sure replace the wires, only with MC (Tousley Ford will give you a great price; 10% over dealer cost). While doing the wires, might as well do the plugs, too. Again, only MC. Not a half-bad idea to replce the coil packs on each cyll bank, too. Do this first before you waste you time on anything else.

Jim

 

You can buy a set of MC wires from rockauto.com for $65.79 plus shipping.

 

i found out it is cylinder #3 low or no compression mechanic says it is a bad cylinder and he is going to put air in it to find out what part is leaking , everyone i talk to says it is more then likly a valve sticking or something , is this a common thing with these trucks and if it is a valve sticking (exaust valve i would believe ) what is cheapest fix ?? i am running out of money and i just got this truck ,

 

also was wondering where you get motocraft plugs as i am from ontario canada and have not heard of the make , do you get them from canadian tire or any ford store??

 

Time to cut your losses and find another vehicle. You got screwed. This repair can approach the value of the vehicle.

Bad gas my *** - he saw you coming. That truck has been ridden hard and put away wet too many times.

 

if you want this truck. give it a good tune up, motorcraft plugs and wires. coil packs should still be good. If not replace those too. clean the throttle body, IAC valve next to it, run some seafoam thru the brake booster line before the tune up. new airfilter and fuel filter.

 

oh have you thought about dropping the tank and cleaning it out thoroughly?

 

None of that is going to fix a cylinder with low or no compression.