I drove my 92 f-150 302 up to upstate NY. The truck was running awful. IT was bucking bad any time you hit the gas. It rattles and shakes bad. It runs really smoth when the rpms are at like 2000. Or when it is idleing in park. I am going to pull the cats off and run pipe to see if that makes any differance. If it makes a difference the tube coming into the air box from the vaulve cover is putting oil into the air box. just a little but over the trup it added up. Please help me i have to drive back tomarow afternoon.
Thanks in advance
Dan

 

This seems to be a common occurance this summer... I'd start with a tune up, use NAPA, CARQUEST, or Advance PREMIUM wires, cap and rotor. Motorcraft spark plugs, and then use a napa ICM. The cheaper line of ignition parts just aren't very good.

 

When you say a little bit of oil that added up it makes me wonder if the air filter needs to be changed. Is the PCV stuck? Although I don't think the PCV would cause this much of a problem. A vacuum leak may, especially if it affects your timing advance. An easy check of your fuel pressure regulatior would be (with the engine off) to pull the vacuum hose off and see if if gasoline has made it though the diaphragm which would be a bad thing. Way down on the list of things to do would be to think about changing the fuel filter.

 

Don't mean to pour salt in your wounds, but check the seam between the plenum and intake. Then, take a look at my gallery and see what you may be up against. The tear-down only took about an hour, and shouldn't take much longer going back unless you decide to change the O-rings on the injectors while you're in there. Then, for obvious safety reasons, you'll want to check for leaks before you put the plenum back on. It is extremely possible there is a vacuum leak around the o-rings at the bottom of the injectors (intake end). When you get it home, I'd recommend doing the job again so you can clean the injectors if the performance doesn't improve. I'm probably gonna 'rod' my cats this weekend too, because even after complete tune-up, repairing the plenum leaks, compression checks, blah blah blah, NO codes from the computer, still heavy throttle miss. Unfortunately, to 'rod' the cats, gonna have to drop the tranny cross-member to get the Y and cats out (one piece). Cats are buzzin like crazy at low RPM, and have been since I had Ford Racing shorties put on it to replace broken manifolds. Now, as for the oil going into the plenum from the PCV line, that sounds a little more serious. The only way oil should be getting up that high, is for it not to be draining back to the pan properly. Sounds like some pretty serious blow-by happening, and hunting a way out. Check the oil closely, and make sure it isn't getting milky looking. If it is, find a friend with a piggy-back truck to come and get you. You really don't want to drive it if there's coolant going into the oil.

 

the truck made it home. I just cut the pipes before the first cat and ran stright pipes to glasspacks. Took a few hours at advance auto to find enough peices to patch it together. It ran a little better. I took of the throtle body today and the intake manifold has a ton of build up on it. I can Scrape off chunks with my finger nail. so what exactly did you do in those pictures? That is what mine looks Like. There is no coolent in the oil. and the oil in the air box stopped. THere wasnt enough to even cloge the air filter a little. there was just some on the box. I found a broken vacume line. It is the white one that goes over by the blower mother. It has something to do with the heating i asume but How do you fix rotted lines?
Thanks Dan

 

you can probably patch up the broken line with a peice of rubber vaccum line

 

i dont think that will work considering it is one of those extreamly small lines. I have pictures of the intake and throtle body in my gallery. I now have taken the throtle body apart to clean that but I am not completely sure what old paint was telling me to do. It seems like the same thing as his. The plugs also have to get replaced.
Thanks Dan

 

OK so When I was cleaning the throtle body, I pulled the gasket off and there was a rather large amount of oil behind it. There are pictures in my galery. This Is a Rather large problem right?
Thanks Dan

 

Depends where the oil is coming from and why/how.
How much oil do you lose? Oil going through the intake is bad, not as bad as water would be though.
It's possible your PCV valve failed and the oil got sucked through the intake. If thats the problem 5$ should fix it.
You can get that extremely small plastic vac line and rubber connectors for them at the parts store. Just clip them where its good and slip on the rubber union, then run the new piece wherever you need. My parts store had it in the 'stop' racks, with the window cranks and whatnot.

BTW I pulled my upper and lower intake and sent it to the machine shop and had them both dipped. They came back nice and clean. I almost pulled the heads and sent them too, but thankfully some friends talked a little sense back into me.
Did it start after anything in particular, passing, high rpm; what type of country: hills flat.... What's your driving style? slow and steady; occasionaly let her run; or use whatever shes got.

How many miles since your last oil change, how dit it look?

Above 2000 rpm it gets bucky huh. Did it feel like it was misfiring/wanting to backfire, or more like when you run out of gas?

 

It felt like it was running out of gas. I havent owned it for that long. I gont know when the last oil change was. I have put only a few hundred miles on it. Where is the pcv? I have heard alot about it but i dont know were or what it is. When we noticed it we were driving and average of 75 mph when we used it but we wernt hammering it to get there.
Thanks Dan

 

Depends where the oil is coming from and why/how.
How much oil do you lose? Oil going through the intake is bad, not as bad as water would be though.
It's possible your PCV valve failed and the oil got sucked through the intake. If thats the problem 5$ should fix it.
You can get that extremely small plastic vac line and rubber connectors for them at the parts store. Just clip them where its good and slip on the rubber union, then run the new piece wherever you need. My parts store had it in the 'stop' racks, with the window cranks and whatnot.

BTW I pulled my upper and lower intake and sent it to the machine shop and had them both dipped. They came back nice and clean. I almost pulled the heads and sent them too, but thankfully some friends talked a little sense back into me.
Did it start after anything in particular, passing, high rpm; what type of country: hills flat.... What's your driving style? slow and steady; occasionaly let her run; or use whatever shes got.

How many miles since your last oil change, how dit it look?

Above 2000 rpm it gets bucky huh. Did it feel like it was misfiring/wanting to backfire, or more like when you run out of gas?

 

a good rule is to not drive a new vehicle until you change the oil/filter, fuel filter, check plugs/wires/dist. cap and all the other fluids in the vehicle.

to not do this and take it on a long trip at 75 mph just does not make sense to me.

i am glad you got it home

 

thanks for the help. I started a new thread. This one isnt really getting at what I need.