View Full Version : Whats wrong with my ford?? please help!

05-04-2008, 06:15 PM
So i bought a 1990 f-150 efi 302 5 speed 250xxxklm.
full length headers. dual exhaust
6 inch suspension lift

So my problems are as follow.

1) Burns through gas like it's going outta style 120k to a tank..smells like its burning really rich....? and thats without putting my foot into it.

2) Oil pressure wont stay up as soon as truck gets warm oil pressure plumits unless the rpms are above 1500...? ive been told that i can try putting a high volume oil pump in....but id rather fix it right than rig it together for a couple months till i blow the whole motor.

3) The other problem is whenever i go up or down hills whether i'm accelerating or not my truck starts to shake violently from side to side no clunking but it feels like it's getting no gas. but i can accelerate with no problem but it doesnt stop...it's an ugly ugly shake. feels like my whole truck is going to just go boom....? but only does this on hills.

4) i do however know that with efi i should have an o2 sensor in the headers and i crawled under the truck to see if it was there and i couldnt see one...? So im not sure guys and gals so any help would be awsome.

thanks for any and all your help.

05-04-2008, 06:36 PM
1) do a full tune up and includeing fuel filter i would do o2 sensors too i was geting really bad milage on my ploder and that increased it alot

2) no idea

3) did the put blocks in the rear to lift it?....they could have the pinion angle way out in the rear causeing viberation

4)some times there in the exhaust and not on the headers im not sure on those motors mine are in the down pipes.

05-04-2008, 08:21 PM
sorry to say but the first problem is that it is a ford, I have a 1991 f250 that gives me nothing but problems, but good luck I hope you find the problem faster than I have

05-04-2008, 08:27 PM
sound like it more than one thing start with a tune up with replacing the o2 sensor

05-04-2008, 09:07 PM
Its a ford nothing else need to be said

05-04-2008, 09:45 PM
don't trust the oil pressure gauge, my '90 Bronco with the same set up had the same signs, after researching it, I found that the gauges were problematic. Install an after market one.

05-05-2008, 05:37 PM
motor is fucked if your oil pressure drops to 0 at idle when warm.

05-05-2008, 05:40 PM
did you buy that truck from a guy in winfield by any chance?

05-05-2008, 06:44 PM
You got no O2 sensor probably so it runs in a failsafe rich mode. So you'll need a sensor installed and probably need new plugs cuz yours will be fouled.
The oil pressure is probably fine if it fell to 0psi your lifters wuld collapse and make one hell of a racket. The gauge showin 0 at idle is really common in those trucks both mine did it and the one owned by a friend now still does.

05-06-2008, 12:00 AM
timing being off could cause the engine to shake and wouldnt be good for gas milage

05-07-2008, 12:14 AM
Dont go by the factory oil pressure guage, its inly a switch and only needs +5psi to read normal, and half of the time the sending unit is toast, get a mechanical guage. The o2 sensor should be in the Y-Pipe where the 2 sides meet just befor the cat. As for the shaking, bad pinoin angle wouldnt cause side to side, sounds like either your tires are way out of balance or something in your steering is f'ed. As for shitty milage, change the oil, air, and fuel filter, new plugs and wires, might as well do cap, rotor and coil, who knows when they were done last, MSD coil and ford racing plug wires and gap the plugs out to .055 with a base timing bump to 13 degrees BTDC seems to help these trucks out quite a bit, I have the same set up in my bronco and get 21mpg on the hyway doin the speed limit.

05-10-2008, 11:42 AM
So.. ive taken all of your advice...and well i still have the rocking and shaking problem.sooo. The only time it does this is when the rearend is under pressure....like going up a hill coming down a hill or if i put my foot into it in
1st or second gear...and when it starts doing this if i brake and come to almost a complete stop the truck stops acting up...? so im pretty sure this all means that my rearend is shot....?

So if anyone could either pin point possibly what is wrong with the rearend or if they can or know someone who can fix it..that would be great i'm on a limited budget...for this fix and i have no idea how to do a rear end not even a little bit...so any help would be great.

05-10-2008, 01:26 PM
dave, where are u living and what u doin tomorrow? meet up with me and clayton and ill take a look at it.

05-10-2008, 06:46 PM
that or i can swing out by your place this week.....I got some mothers day stuff to do tomorrrow but i'll be in winfield tomorow afternoon.

05-10-2008, 06:51 PM
thats what u get for buying a ford [36][36][36]

05-10-2008, 08:17 PM
801 9448. call me

05-11-2008, 06:55 PM
So i'm still looking for help with my rear end so again if there is anyone out there who has or can rebuild my rearend in my truck would be awsome.

05-21-2008, 07:32 PM
As far as the fuel things go is there a check engine light on??? dose it come on for a few seconds at start up and then go off???
You need to scan codes...
The fuel pressure regulators are a problem on that era of F truck they leak internally and just suck the fuel onto the intake....
As for the shaking is it shaking in the seat or the steering wheel???
It could be loose parts... Dosn't sound like a rear end to me (but who am I to know I've only been a mechanic for 20 some odd years and most of those with ford)...
Get under it and look for loose or broken parts...U-bolts, front end parts, U-joints, incorrect pinion angles???
Good luck Randy...