cold idle problem
Thread Starter
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Senior User
Joined: Jun 2003
Posts: 238
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From: Virginia
cold idle problem
When I start m truck, it will idle up high (not too high), just high enough to get my vacuum up to like 18-20 inches. This will last for about a minute. The, the system acts like it's searching for the best idle. The RPMs will slowly start to cycle down until thr truck dies (takes about 5 mintes after starting to do this). If I restart the truck, the same thing will happen. There is no problem restarting, she fires right up.
If I drive away cold, the engine will pulse when I idle. Like, if I roll up to a stop sign, the engine will surge or pulse about once a second, and my vacuum will be really crappy, like 13 or 15 inches. There is a slight hesitation when I take off from the line, like the truck is going to die. Then it picks up.
After about 2 miles, the truck starts to warm up and the idle goes all warm and fuzzy. When I got home friday (it was about 70 degrees outside) the einge was nice and warm. I pulled into the driveway and the engine was purring with a failry low idle and sitting at 20 incches of vacuum.
I am suspecting the IAC or the engine temperature sensor. I don't really know why the IAC would care what temperature I am at (seems like it would work poorly no matter what it if was cruddy). I replaced the IAC last summer. I am planning on cleaning it, but I really don't think the symptoms fit that bill.
Does anyone else know what I should try? I have checked my vacuum lines. They are all new, even the lines on the TB and the line back to the tranny. I replaced my upper intake gasket and my TB gasket the other day, so they are fine. The fact that I can get the 20 inches of vaccum when the engine is warm makes me think it's not a vacuum leak.
Any ideas?
If I drive away cold, the engine will pulse when I idle. Like, if I roll up to a stop sign, the engine will surge or pulse about once a second, and my vacuum will be really crappy, like 13 or 15 inches. There is a slight hesitation when I take off from the line, like the truck is going to die. Then it picks up.
After about 2 miles, the truck starts to warm up and the idle goes all warm and fuzzy. When I got home friday (it was about 70 degrees outside) the einge was nice and warm. I pulled into the driveway and the engine was purring with a failry low idle and sitting at 20 incches of vacuum.
I am suspecting the IAC or the engine temperature sensor. I don't really know why the IAC would care what temperature I am at (seems like it would work poorly no matter what it if was cruddy). I replaced the IAC last summer. I am planning on cleaning it, but I really don't think the symptoms fit that bill.
Does anyone else know what I should try? I have checked my vacuum lines. They are all new, even the lines on the TB and the line back to the tranny. I replaced my upper intake gasket and my TB gasket the other day, so they are fine. The fact that I can get the 20 inches of vaccum when the engine is warm makes me think it's not a vacuum leak.
Any ideas?
Thread Starter
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Senior User
Joined: Jun 2003
Posts: 238
Likes: 0
From: Virginia
I just checked the ECT and the ACT and they both seem fine. I checked them at cold and then again when the engine had warmed up.
I noticed that my injector for #2 (the front driver's side) cylinder is clicking pretty loudly. I probed it with a scrwdriver and there seems to be more mechanical noise on it than the others on the dirvers side. Is that normal?
I noticed that my injector for #2 (the front driver's side) cylinder is clicking pretty loudly. I probed it with a scrwdriver and there seems to be more mechanical noise on it than the others on the dirvers side. Is that normal?