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Discussion Starter #1
Ok, so this problem has been confusing the hell out of me. I have called the tech department at LC engineering and they seem to be confused too. This problem has been going on for about a year, but it's never been consistent enough to figure out what it is.
Here is some info on the truck.
1990 pickup with a 22re. 201k on the engine and 120K on the timing chain (I'll be replacing that soon) Plugs/wires have 46K on them and the cap and rotor was replaced last night. Valves were adjusted 23K ago and the LCE matched flow injectors were installed 17K ago.

So when the truck sits for at least 8 hours sometimes it misses at idle when you first start it. It starts right up and pretty much runs on 3 cylinders for 30 seconds or less. After that it's fine and there are no running issues. For the past year it's has been doing this very inconsistently. Sometimes it would do it for 3 days in a row, other times it will go 3 weeks without having any issues. Now the problem seems to be getting worse. It seems to do it more often and now it will stay on 3 cylinders for more than 30 seconds. Once you let it idle for a minute it will go right back to normal. But now it will sometimes miss in the very low RPM (1500 or less) range until it warms up. Once it's warm it's all good and confusing as hell. The problem really started to get worse last week when we had rain for 2 days in a row. I wonder if the extra cold temp or the humidity is causing it to be worse.

I don't seem to have any power loss or fuel mileage issues. Last night I replaced the cap and rotor as a starting point to see if it will change anything. I took a different car to work so my truck can sit extra long and hopefully I can see if the problem is still there or not when I get home. If the problem is still there I will check the valves tonight to see if anything is out of adjustment. I also thought about checking the injectors, but the problem only lasts for a few seconds which isn't enough time for me to check all 4 of them.

The only other issues I have is that my check engine light will come on and off sometimes (3 or 4 times a month at most) and it only does it on my drive home from work in 4th gear with light throttle. I'm not sure if this would have anything to do with my idle issue. When I check the codes it has two. One is engine lean, the other is engine rich.

Has anyone else experienced an idle issue like me? I've searched all over the place, but I can't really find anyone with the same symptoms. Any help is appreciated, even if it's just a suggestion to point me in the right direction.
Thanks.
 

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My 3rz has an identical problem. I scoped down the spark plug holes and turns out i have a cracked head. Coolant seeps into # 3 cylinder giving it the same miss on cold starts. Check your coolant level, head gasket or cracked head could cause your issues.
 

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I agree with above, Supra I have had the same symptoms and the head gasket blew after some time. I would also recommend pulling the plugs and looking for any signs of excessive fuel or coolant. Toyota plugs for 22R were only designed for use of 30K miles. Might want to replace them.
 

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Discussion Starter #4
Worked on the truck tonight. Cap and rotor along with adjusting the valves didn't help at all. Tomorrow I'm going to replace the plugs and wires. The plugs looked good last time I checked them (about 5,000 miles ago) when I checked them I also did a compression test. The front three cylinders were 185psi and the rear cylinder was 190. I don't think much has changed in the last 5k but I guess you never know. I'll find out more tomorrow. I'm hoping I have a bad wire or a tired plug.
 

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My 3rz has an identical problem. I scoped down the spark plug holes and turns out i have a cracked head. Coolant seeps into # 3 cylinder giving it the same miss on cold starts. Check your coolant level, head gasket or cracked head could cause your issues.
Was there any smoke out the exhaust when starting for the first time of the day?
 

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Discussion Starter #7
I don't have any smoke either. I'll see what new plugs and wires do for it later today. I'm hoping I don't have a crack. I guess I'll find out sooner or later.
 

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I had an issue similar to this that turned out to be a broken fuel injector wire inside the harness. 25 year old wires get brittle. When it heated up and expanded it would make good contact but when cold or intermittently it would break the connection and not fire the injector.

Try to isolate which cylinder is causing the problem by pulling a spark plug wire one at a time while the problem is occurring. This will at least give you a place to start.
 

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Discussion Starter #9
I found the issue.

I guess the plug had a small crack in it the whole time and then it finally went. That explains the loud valve train noise I heard. It was that part bouncing around. The truck still has good compression and it runs great so I won't worry about the cylinder right now.
 
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