New-to-me 1990 F150 Lariat 4x2, 302 engine automatic with 126k miles. Got it from my grandfather yesterday in NC and had a hell of a time getting it back. The old man said he is flabbergasted and never had any trouble with it, but it broke down on me three times over the course of 200 miles.

It ran great on cruise control with AC going full blast until about 75 miles into the trip -- about an hour. It felt like the engine was getting ready to stall out or that it was shifting back and forth in and out of 3rd and 4th gear -- shuddering and all. It happened the first time since about 10 minutes into the trip that I had to slow down to merge from the interstate onto the highway. From there, not good. No power going up hills and the power train would get herky jerky. Give it gas and it was start knocking like the engine or transmission was going to fall out from under the truck. Pulled into a gas station and it died. Let it cool down for 15 minutes and it ran OK for maybe another half an hour. Rinse, repeat.

I was cautioned to let the engine warm up or it would stall when turning on the AC. Now, unless you hit the throttle and hold it at 1,000 RPMs for a minute or so, it will just start and stall.

To the good part, my grandfather called me today and said he'd forgotten he had knocked a hose loose (I love old people). It is the hose flagged with what was green tape that looks white in this picture -- the one coming out from under the air filter box going to the neck of the oil fill cap. It's back on, but the retainer clips are barely holding it on there. What is this? What does it do? Would this cause any of the symptoms I'm suffering?


truck2 by cmdumond, on Flickr

I put it back on and it doesn't fix the idle/stall problem. Taking it in to the shop tomorrow.

 

could that be a vacuum line?

pcv valve prehaps ?

i'm guessing here, but if it's the pcv is stuck, it may give you issue... only $7 to replace.

 

Well since you're taking it to a shop they might find whats up.

I would suggest having the fuel pressure checked at the fuel rail if the pump is working properly.

 

That hose is the crankcase breather.should have breather filter attached to it inside the airbox. Should not effect idle at all. Edit.....actually, mine did the same thing when my ac compressor went bad. My sons toyota also had the same issues yesterday when his ac compressor went south. Just guessing.

 

It's the hose that goes to the breather filter. When you remove the air filter, there's a small white filter in there that it connects to. It won't cause the truck to shut down.

But, if you have a bad, clogged or otherwise defective PCV valve, it will spew oil through this hose through the breather filter and down through the drain holes in the bottom of the air filter box.

 

Well... Considering i didnt know what i was talking about... Not bad for hung in the same ball park.

I got a feeling this would cause the op's truck to kinda run rough....?

 

The 90 version has an IAC valve.

 

I've left mine loose a few times and it ran fine, but I did smell a strong fuel/oil odor on the inside of the cab each time I did so.

 

Theres another thread that a guy was talking about fuse #9 and a fuel sender relay.... I think.

 

It could be a number of things, but what I'd look at first would be the ignition module (and/or the entire distributor assembly), ignition coil and I'd check the fuel pressure.