My tach reads way to high. What could cause it to read so high? It say i idle at 3000 rpms and cant figure out why.Is there a sensor or connector that goes bad? or do these tachs go bad?

My service engine comes on about 10 minutes of driving and goes off a couple minutes later . Then it comes back on later. The engine only has around 100 miles on it since i built it.It didnt start coming on around until around 99 miles. I connected all the sensors and checked all the connectors.How do i check the diasnoc connector which 2 letters do i run a wire to , to find out a code?

I still have the idle problem. I checked all the vacume lines and there connected right. The car has had the idle problem since 1999 before i built my engine. Now it does the same exact problem with the new engine. It idle up and stays up for a while then it idles lower and stays for a while. It goes back and forth way to much.If any one has anymore ideas please let me know. The old and new engine had the same idle problem .So i dont think its the engine.Thanks

If you have an Auto Zone or Advanced Auto near you, they will check your codes for free. At least it's a starting point.

http://www.z28.com/forum/images/smilies/z28rocks.gif I had my car hooked up to a big diasnoc today and everything checked out ok. I had to re adjust the throttle position sensor it was adjusted wrong. I had code 22.After readjusting the service engine light didnt come back on and the code disapeared.Ive check vacume lines and engine for leaks but i havent found anything wrong with it. Has anybody have the same problem? I have to figure out something before it causes me some sort of problem in the future. What controls the idle?Does the trottle position control it? I wish it would idle like it is suppose to. Like it did 6 or 7 years ago .The car has had the idle problem since around 1998 before i built my engine. Now it does the same exact problem with the new engine. It idle up and stays up for a while then it idles lower and stays for a while. It goes back and forth way to much.If any one has anymore ideas please let me know. The old and new engine had the same idle problem .So i dont think its the engine.
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