r.barn

been having vapor lock problems on my stock 5.0.

only does it if I drive more than 20-30mins non-stop

Put in new fuel filter, still having problems on long drives.


Any thoughts?

PRO50SC

Very vague discription. What kinda car and exactly what does it do?

Twisted

If you're sure it's vaporlock, I would guess maybe your gas cap isn't venting properly...if you're sure it's vaporlock. I'm trying to apply motorcycle logic to cars, but I suspect it applies.

r.barn

ok, sorry,

Stock 1989 5.0 LX vert., VERY original, almost nothing done
to this car or parts replaced.

After car has been driven on freeway for 30mins or more
it will start to stall out when you put it in idle or just let up on the accelerator
and if i try to give it more gas it will stutter and jerk and eventually die.
Seems to be acting like its getting vapor or air in fuel injection system.
Plenty of gas in the tank and I've already tried putting
a new fuel filter in.

Only has this problem after engine gets good and hot.

On just short drives to the store it runs fine and has plenty of power.

PRO50SC

Possibly the converters are clogged. How many miles on it? Does it run ok until that point. Could also be a fuel issue.

r.barn

apx. 95,000 miles, runs great until I drive it on the freeway for a half hour or more.
thought it might be a dirty fuel filter and just wasnt getting enough gas thru to keep fuel
from boiling in the fuel lines on top of the engine, but replaced filter and still have probs.

could the fuel pump be going out and it still run ok when relatively cool?

Even if a i flogg it, it runs fine and seems to be getting plenty of fuel.

Converters? you mean the Cats?

again, runs fine until it gets hot.

90GTRagtop

Not likely at all to be vapor lock. You have an electric fuel pump in the gas tank that pushes fuel through the lines. Vapor lock occurs on the suction side of a pump when the line gets hot. Like Pro50SC said, it could be clogged Cats. How does your exhaust sound and feel? Also could be something electrical breaking down when it gets hot, like a coil or ignition module.

r.barn

Vapor lock also occurs in fuel injected engines when not enough excess fuel is being
pumped thru the system to keep the fuel lines cool so that the gas doesn't boil in
them before reaching the injector. Gas litteraly turns to vapor in the fuel line
just before being shot into the engine. Have trouble with it all the time in my airplane
when trying to start it HOT, just cant get liquid fuel into the cylinder.

Thanks for all yalls feed back, this has me stumped a bit and I dont want
to start just throwing money at it.

Keep em coming.

PRO50SC

I work on alot of different f/i engines and I can honestly say that I have never come across it in all my years. Not saying it can't happen, just that symtoms like yours were caused by something else.

PRO50SC

Any chance you can hook up a fuel pressure gauge while you drive and see what the pressure is doing. Also, it could be a volume problem as well.