Rough idle after high speed (1 Viewer)

[WarriorJ]

Hey people!
Problem with my 94 fj80.
If I'm on the back roads keeping it under around 30mph it wont happen, but after I've hit the freeway and coming to the stop light, it always rough idles, sometimes dies. Happens almost everytime I've been driving high speed. I'll put it in park, hit the gas to rev it up and it evens out back to normal everytime as well, but the problem still unknown. Is this most likely a vacuum leak somewhere? I heard brake booster can cause this? Anyone know?

 

[Red Merle]

Clean out your throttle position sensor and make sure it seats properly and the wires are in good shape.

Also check your throttle cable and see if it can move freely.

Also easy to jump the wire on the EGR on a '94, which eliminates at least half of the vacuum lines.

 

[Proven]

Rough running engines after high throttle usually is an issue with fuel, leaking intake or throttle position sensor. Or all the above.

With fuel injection, fuel is usually a lesser likely issue but worth verifying.

Never underestimate checking the grounds and the wire loom around the EGR.

 

[Rifleman]

Have you checked to see if you have any trouble codes logged in the computer?

 

[MidMan]

This problem usually appears when fuel valve (which is attached almost with fuel pump close to nossels) is clogged. Here we call it fuel reverse valve or sometime pump reverse valve.
At high rpms it will work fine. But at low rpm it will block the fuel supply and hence causes rough idling or sudden stop.

Either you can clean it well and fix it back to see if it works. If yes you are lucky. If no, then consider replacing it.
Hardly 5 minutes job.

Hey people!
Problem with my 94 fj80.
If I'm on the back roads keeping it under around 30mph it wont happen, but after I've hit the freeway and coming to the stop light, it always rough idles, sometimes dies. Happens almost everytime I've been driving high speed. I'll put it in park, hit the gas to rev it up and it evens out back to normal everytime as well, but the problem still unknown. Is this most likely a vacuum leak somewhere? I heard brake booster can cause this? Anyone know?

 

[WarriorJ]

This problem usually appears when fuel valve (which is attached almost with fuel pump close to nossels) is clogged. Here we call it fuel reverse valve or sometime pump reverse valve.
At high rpms it will work fine. But at low rpm it will block the fuel supply and hence causes rough idling or sudden stop.

Either you can clean it well and fix it back to see if it works. If yes you are lucky. If no, then consider replacing it.
Hardly 5 minutes job.

Thanks flr all the replies fellas. I ended uo getting it sold before finding the issue, but obviously let the guy know and experience issue before he bought. Onto new problems with my 95.