I have a 1990 F150 w/ a 302 5spd. For some reason it has not been sounding like its normal self. There is an "air" sound while running. Like someplace it is forcing air out. I also noticed that when I turn sharp or hit the brakes hard, the oil pressure gauge drops like a rock to nothing and the check engine light comes on. There is too much oil in it, which I will alleviate ASAP. Why would the oil pressure drop like that? Especially with oil in it?

 

Sounds electrical to me, seeing as WD40 or duct tape won't work lol



Possibly a ground problem or vacuum leak? The air whoosh sound, there's a coffee can under the hood of my 300 that has a about a 1 inch diameter pipe sticking out of it towards the firewall that just blows out warm air, I'd imagine it's smog related, it's possible that's blowing harder than normal?

I'm just throwing ideas out, I haven't heard of your problem before and haven't had it happen to my truck to gain the knowledge about it

 

i would say vacuum leak, since vacuum helps power the power steering and brakes, dont know why the oil pressure would drop like that. mine does it too from time to time, i think the sender is bad for the oil pressure gauge. that is pretty common. they could be two separate issues

 

Normally the oil pressure is on the "m" in the NORMAL range, but when cold it will be in the "A" range. I have no earthly idea about the sound. I know the coffee can is emisions related, was told by a mechanic. I will drain some of the oil off tommorow if I can. It just now started doing this with the pressure gauge. That is what I am truly worried about. I changed the oil in early July, and it is already black. I only drive maybe 2000 miles in a year, so it has very few miles on it since the change. I do have an oil leak, but cannot find xactly where it is coming from. Want to find a way to fix this thing. I love the truck and want it running the way it should, not acting like it is about to give up.

 

Problem solved

 

What was it?

 

maybe you should seafoam the engine, that will help get deposits out of the engine, which may help the oil turning black soon.

 

Oils already black. I took some of the oil out, until it was low, then added some back. Now it runs fine! Just like it did before. Only thing is now i cannot see any oil on the dipstick, but the light is not on and the oil pressure is fine. What is this "searfoam" and how do I use it?

 

here's the link for what seafoam is, i'll try and find the nice write up on how to do it on our trucks thats for ya.
http://www.seafoamsales.com/motor-treatment.html

 

here's the link, with lots of nice pictures to go along with it https://www.f150forum.com/f33/how-se...-1991-a-31505/