Hey guys, i have a 1989 toyota pickup that my family has had since i can remember. It was my brothers first car and it was passed down to me. I absolutely love this truck but it doesn't feel the same about me. Ever since we've had this truck its had these two problems that we could never figure out. Random idle drops. Now what i mean by random idle drops is that it'll idle perfectly fine 800-900 but there are times and this happens everytime i drive it for a while the idle will drop to about 500 rpm almost stalling. There are even times where it does stall (This is more rare). It's like the truck wants to die. Now here is the weird part, when its idling at 500 rpms it'll randomly start to climb and go back to 800-900 rpms and stay that way for some time. And if i hold the throttle at 800-900 rpm for awhile and release the pedal it'll stay there. Now the second issue is a nasty sputter/misfire. While the truck is idling it'll sputter, its not a timed sputter but different every time. Sometimes it'll sputter 4 times in a row and other times just one. Also when driving full throttle sometimes it'll sputter causing the truck to stop accelerating for a moment and then return after.

I'm hoping that somebody here will be able to help me find the problem my brother could never find. If you need a video for the idle and sputter i will gladly make one. Thanks, Kevin.

 

Superficially, it sounds like the igniter module may be suffering some strange issues.

Troubleshooting periodic malfunctions is difficult.

Have you tried checking for any trouble codes?

 

Not exactly, there isn't a check engine light so i didn't think there were any codes.

 

Some codes are "sticky" and once the CEL is lit, it stays on; others aren't and will either not keep the light on across engine restarts or will go away immediately when the problem disappears.

 

Well ever since its been in my hands i've never seen that light go on other then before it starts.

 

May still be worth pulling codes though.

 

A proper tune-up won't hurt either.

 

Any chance you figured out the issue with your pickup? Mine seems to be doing pretty close to the same thing. I have a 96 tacoma 2.4 liter and it has stalled on me a couple times while driving just at random. I had the spark plugs and fuel filter changed, even added some injector cleaner but no luck. I took it to the mechanic and he did a bunch of diagnostics but couldn't figure out the problem. He checked the ignition coil, said it wasn't anything electrical, checked some other stuff but of coarse it never stalled on him. Two days after getting it back I started it up it ran for about a minute then started to sputter, almost died but caught itself and revved back up for a bit then died. And it kept doing this, it would idle for a bit then all of a sudden cut out and almost die. Today when I started it it never dies but when I rev it, it just doesn't sound right, kinda makes a sputter or cut out sound.

 

I wish I could tell you I did. I just temperarely fixed it by bringing the idle up 300 rpm now running at 1100-1200 and when the strange idle change comes it drops to 700 instead so it isn't as much as a bother. I still plan on hitting this problem head on but for now I just want it to drive. Also the sputter was never fixed either. If I ever do fix it I'll gladly post it up to help any others with the problem.

 

run a bottle of seafoam thru, techron concentrate in the gas tank, and clean the MAF. Should fix it.

 

After recently changing the tps and cleaning the afm on my 89 22RE I had a similar problem. I'm not positive this is the culprit but you can easily check it to see if it it - the dashpot may be sticking. The dashpot is on the throttle body just below the pulley that the throttle cable attaches to. It is there to keep the throttle from slapping shut when you suddenly let off the throttle. If it is gummed up it will hang up about 3/4 of the way shut or so. I figured this out by starting the truck and letting it come up to temp so that the idle fell to it's normal range (750 - 800 rpm). With the engine running, push the throttle body fully closed by hand. At this point see if your idle drops to the 500 rpm you stated before. What might be happening is that you are setting your idle speed with the dash pot (throttle plate) partially open, giving you a false base idle speed. If the idle drops at to 500 rpm like before, reset your idle speed with the throttle fully closed. I took my throttle body off and removed the tps (important to not get cleaner on the tps), cleaned the throttle body, removed the plastic cap and filter from the dash pot and cleaned them with carb cleaner. Lubed the dash pot mechanism thoroughly with silicone spray, reassembled, set tps properly, and re-installed. Now my throttle returned to fully closed as it should. Lastly I set the base idle speed (with engine properly warmed up) and walla. Hope this helps.