new owner with some questions

[onthego]

Hi, i just came into the ownership of a 1974 FJ40 with the F engine, a 4 speed and a tiny bit of rust (just on the sill) and had a question.
First, i live above 9000ft, so i am used to carbs playing silly games and performance being silly.

today when i took the fj out at first it was fine and then on my way down from the mountains, it started acting oddly, like it wasn't getting any gas. it started sputtering randomly and then when i came to a stop at a light around 8000ft, was trying to die and wouldn't idle.
i turned around and headed home. i found if i pulled the choke slightly out it ran much better, and on the ride back up elevation, it ran fine, no sputtering, no backfiring, and it ran pretty strong.
the previous owner had a locking gas cap on it, which was vented, but every time i pulled the gas cap, it was sucking like there was a serious vacuum.
before today, it was acting fine, and didn't have this behaviour. I searched on the forum, and saw some ideas, such as getting an oem vented cap, that the cap might be somehow causing a vapor lock, and to check through the lines. I'd appreciate it if anybody had any other ideas that might help me to figure out what the culprit may be.
i noticed the gas tank was even acting like this at 5000-6000ft.

 

[onthego]

scratch the efi question, i was searching and found some pretty good threads covering it.

 

[Butt Ugly Chuck]

Running better with the choke on sometimes indicates a vacuum leak.

Butt

 

[steverb]

replace cap and roter. points and condenser if you have them.

 

[onthego]

i replaced the gas cap, and checked the vacuum lines. i took it out this morning, and it ran fine on the way out, most of the way back, and was idling fine when i stopped.
could it be possible there are debris in the fuel tank as well.
i'll replace the rotor and cap next on the list, see if that helps.
thanks for the input.

 

[D'Animal]

Fuel filter?



Welcome to MUD

 

[onthego]

i'll check the filter, i'll pull it and dump it to see if there is a bunch of stuff in it, but it looks good, and seems to be passing fuel fine. i just took it out again after looking at the cap, rotor lines again. cap and rotor are newish, have almost no wear. fired it up and it idled fine, ran fine, let it sit and it idled fine again.

i'll keep digging, thanks for the responses.

 

[onthego]

my next question. i was looking at what is left of the emissions system, the previous owner must have pulled the air pump and most the rest, but i was looking at the air injection manifold and there is a spot where they had taped over it, and under the tape there was a hole where it looks like it rusted through.

What type of impact would that hole in the air injection rail cause? is there a way to remove it and cap it, or what else can i do?

 

[D'Animal]

Do you need to smog your rig?

 

[Fast Eddy]

You could patch it with some radiator putty to solve the immediate issue, then either find another one if you need to smog it, or take it out and get some plugs. The actual specs for the plugs can be found with a search.

 

[onthego]

don't need smog, i'm just wondering if this has something to do with the odd issue i have been having.
for now, i am going to patch it and see if it helps, but in the long run will plug it since it's not a necessity.
i just wonder if this is causing my sputter and idle issues or if it has anything to do with much of anything.

thanks again.

i guess this is more on the exhaust since it doesn't go into the manifold, but it's the only leak i've found so far. one can hope.