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1993 Toyota Pickup
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23 Posts
Discussion Starter · #1 ·
1993 Toyota Pickup 2wd 22-RE 5-speed, 201K, 40~ on engine

I've looked around the forums, and haven't found anything to answer this question.

Recently, I've noticed at stoplights that when I brake, the engine cuts out. It doesn't die, but the RPM's drop low, then back to normal, then low again, then normal, and so on. Sometimes its fast up and down, sometimes it's slower. When I take my foot off the brake, it goes away and idles normal. Today, I noticed it for a little bit when the foot was off the brake, but it went really slow.

Idle speed need adjusted? Timing chain? Brake system needs adjusted? I really have no idea what this could be.

Just FYI, here is a list of stuff I've replaced recently, this might help narrow down what's wrong.

- alternator (2 weeks ago)
- spark plugs (1 week ago)
- starter (month ago)
- cat converter (2 months ago)
- distributor cap, rotor, spark plug wires (2 months ago)

Thanks guys! :)
 

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Bring On The MUD!!!!!
'83 Pickup SR5
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2,334 Posts
either adjust your idle screw or its a problem in the vacuum line. there is a valve i had to replace on one of my trucks at some point but i cant remember which valve it was but the problem went away after replacing it. i would mess around with the idle screw first, its free! that way you wont be spending money you dont have to!

Cam
 

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Soylent Green sales
rock crawler
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12,801 Posts
The most common cause of your problem is the idle speed is set too high.
Check your idle RPMs, and if it's higher than the spec, lower it. It should solve your problem.

Note that other things than a simple adjustment could be causing the idle to be high, if it is.
 

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6 Posts
Hi,

I assume you have vacuum assisted brakes? Check you vacuum line and fittings as well as a bad booster. Sometimes if you have a master cylinder leaking internally it will drip into the booster. The rubber in the booster cannot handle the strength of brake fluid and go bad.

If you just kick it out of gear and coast to a stop does it stall?

Dave
 

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1993 Toyota Pickup
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23 Posts
Discussion Starter · #5 ·
Hi,

I assume you have vacuum assisted brakes? Check you vacuum line and fittings as well as a bad booster. Sometimes if you have a master cylinder leaking internally it will drip into the booster. The rubber in the booster cannot handle the strength of brake fluid and go bad.

If you just kick it out of gear and coast to a stop does it stall?

Dave
Nope, it's only on brake. I can coast fine, it will idle fine, and runs fine normally. Just a weird thing when I step on the brake, and it doesn't happen very often, but has gotten more frequent.
 

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Nope, it's only on brake. I can coast fine, it will idle fine, and runs fine normally. Just a weird thing when I step on the brake, and it doesn't happen very often, but has gotten more frequent.
Hi,
Well then,
Definitely look for a relationship between the vacuum brake assist and the engine. I major vacuum leak (such as stepping on the brake) would cause a poor running / stalling situation.

Dave
 

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380 Posts
Yes, I agree. look at the brake booster. Unplug the big vacuum line going to the booster & plug it. Then start the truck & step on the brakes. If it's gone then you know what ur problem is.
 

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'91 Yota Hilux 4X4
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22 Posts
I had the same problem for a while.

I cleaned the throttle body and it got worse, obviously high idle, so I got the truck to running temp and then lowered the idle to 1000 RPM's with the little screw and it's completely gone.

Hope that helps.
 
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