TylerH

So i picked up a 1992 pickup about 6 months ago. Ever since i got it its ran rough when hot. The engine shakes, kinda like a buck, and sometimes lopes. If i turn it off while its doing this and restart it. All its will want to do is die. I have to feather the gas for about a minute. Then it runs good for about ten seconds. ( ive searched )

I tuned it up. Fuel filter. 3/4 plugs, cap, rotor, wires, and oil. That didnt change really anything. (just runs better high speeds) Replaced the O2 with a used one. Cause the one on it had burn wires from obviuos reasons. I cleaned the throttle body. It was horribly gunky. Peeked in the intake mani and its gunky to. But didnt touch that. Once the TB was cleaned it ran alot better for about a month. Then back to how it was. Check the tb and its still clean.


I dont know if this is related but sometimes it sputters and cuts out when driving. Wont go past a certain speed no matter how much gas i give it. Almost like timing. I have to feather it past the speed then after that its good.

I can take a video of it idling. If that would help. Any idea in the mean time would be very helpful!

TylerH

So i noticed i have a vaccuum line off the fuel pressure sensor thing. The closest sensor to the fire wall.The one with 3 or 4 vacuum nipples. Ill take a picture of what im talking about tomarow. Maybe it has something to do wit it.

myyota

If you have a vacuum leak that can cause a rough idle, but also check the timing and the TPS to see if there set properly.

TylerH

Theres a picture of the sensor with the missing vaccuum hose. I didnt get a video of it running rough cause it didnt do it today. Anyways any advice would be nice

Ill get a better picture tonight.

myyota

You need a better picture, i can`t see anything in that picture.

TylerH

Well i guess after looking at it, its capped. Still dosent look OEM.

Things i forgot to add are it has a exhaust leak towards the rear. And the previus owner replaced the head gasket a few months before i got it. It last but not least it looks like someone start to desmog it but didnt finish. It does not have the tubes that come off the exhaust manifold.

But looks like theres still an EGR. Not 100% sure im looking at the correct thing. Im new to toyotas. Background in diesels. And ive did alot of work on my friends hondas. lol

BajaRunner

The warm start rough idle is most likely due to a sticky/gunked up idle air control valve. Its located right beneath the throttle body.

4-5 phillips head screws take the IAC off the TB and you can clean out the valve which open and closes depending on the temperature of the engine.

TylerH

Do you need a new gasket when you doso? The truck never gets past 1/4 on the temp guage btw.

It dosent sounds like a idle thing. Cause its either running bad or good. Its a straight idle no flucuation. Also dont have a tach so its just by ear. Ill still try it thou. Ill video it tomarow if it does it again.

And i was wrong about my previus post the EGR is there. Just the Pair is gone. No i dont know why.

myyota

That is a factory vacuum cap in the picture. The later model 22RE`s don`t have the smog tubes coming off of the exhaust manifold, my 86 22RE doesn`t have them either.

BajaRunner

Well if it sounds like its just idling low after a warm start (and being too low it starts getting a little rough) I would still say you should take it apart and clean it. Its very common with Toyotas (at least the ones I have owned).

I just bought a 94 22re 2 weeks ago and the first thing I did was clean the IAC which cured its warm idle problems. Now don't get me going on the rest of the other crap I've been through though

I ended up changing the gasket but its an o-ring type gasket that doesn't need to be changed. Just keep it where it is and you should be fine.

TylerH

still has not did it latly. ill take it for a drive later and see.

TylerH

Still having problems. If its hot and i turn it off, then start it again its just wants to die. i have to feather the gas for about five seconds then low idle then straightens out. Maybe cold start sensor or..... o2?

myyota

The cold start injector only operates when the engine is cold, it doesn`t do anything when the engine is warm or hot.

BajaRunner

Like I said earlier it really sounds like an Idle Air control valve (Axillary air control valve in FSM) issue.

You also mentioned the TB being gunky. Well, the IACV sits right beneath it and catches just as much or more of that gunk. The valve is spring operated and will adjust airflow depending on coolant temperature. If it gets stuck, it wont idle right.

If you take it off, clean it with carb cleaner and it still gives you a rough warm idle, I'll pay you $5.

mountaingoat

I had a similar problem, and it was the IAC valve. It wasn't flowing enough coolant, and it "thought" the engine was colder than it actually was.

There's two small coolant hoses going to the valve, one from above sort of by the fuel injector rail, and one from underneath the throttle body. Warm the engine up, and feel both of them; if they are not the same temp, then the coolant is not flowing through and it needs to be flushed.

I flushed mine by pulling off the upper and lower IAC hoses, and pouring hot soapy water into it, then pressurized the line with an air hose to force it through. Reversed the process a couple times to back-flush it, and then rinsed it out with clean water to get rid of the soap, re-assembled, and was home free - good hot idle again.

If it's gunked inside the throttle body, that's a different story; then you'll probably have to pull off the valve and clean the internals as suggested above.

Either way, I bet the valve is your problem.

One more thought: if the IAC cleaning doesn't fix it, I suppose you could try unplugging the cold start injector when it's hot, and see if that takes care of it...although it's true that the CSI isn't SUPPOSED to operate when the engine's warm, if your temp sensor is bad maybe it could still "think" it's cold? Although, I broke a Yota temp sensor once, and the only effect was that the CSI didn't operate at all, making it a bitch to start when cold. YMMV.

TylerH

Sounds like the iacv. Im used to hondas i guess when that sensor gets dirty it bounces like from 500-2500 at idle. I guess these little engines malfunction differnty. When i first got the truck the there was still a little bit of oil in the water. (Blown head gasket i guess from previus owner) Mostly floating not mixed. I flushed it twice or so and now its 99.9% clear. You think that oil in the lines did anything to it? Im assuming yes?

I may pull it off and clean it my next days off. Ill check the hose's after work tomarow.

TylerH

So i checked the hoses after driving it about 200 miles. The top one was a little warmer. No that big of a differnce, but noticable. i think i may take the valve off monday since i dont work and monky with it. Is there any springs or anything that are going to pop out or anything when i remove it.

technojunkie

I had the same problem, clog in the coolant lines to IACV, pressurized air cleaned it right out, no more idle problem.

TylerH

So i attempted to remove the idle air control valve. boy was that a pain in the ass. And a horrible design from toyota. Stripped one. Had to get the dremel out and cut a line so i could use a flat head. Got 3/4 out then i relized there was a four one hiding under the fuel rail. Well kinda agravated me cause i did all that work for nothing. But ill buy a new throttlebody gasket and pull that off soon.

What i noticed thou that the water that came out wasnt as green as when you look in the radiator. And i looked in the radiator to see if had goten lower no it did not. So it must be after the thermostat or i got a clog?

Solomon8

What would you use to clean it?