I got a 1992 Z24 with a 3.1L 5spd. It runs great except once in a while (especially when it's cold or rainy) the idle will pulse. It will go from normal idle and jump to over 1000 rpms, then dip down a little below normal and then repeat. It will keep doing this until I either give it gas or take off. This gets real annoying at stop lights. It had even died on me a couple of times.

I took it to a near by garage and they hooked it up to a computer. It did not show anything wrong. He kept my car a couple of days and said he presure tested the injectors and replaced one censor. I am not a mechanic but I think he said it was an idle-air censor. That did not fix the problem.

He told me that the early 3.1L had notorous idle/ injector problems and there was nothing else he knew to try. I was just wondering if anyone else had this problem before and if there is anything else I should look into to fix this?

Thanks for your help.

U may want to check ur tps sensor. This sensor will not always set a code hard or intermittent.Go to http://www.wellsmfgcorp.com/counterpoint.html and click volume 2 1998 issue 1 and this shows u how to check it with a multimeter.The only other thing may be the map sensor which affects the idle and rpms etc and the same site can show u how to check that doing the search for it there.I hope this is helpful and anything I left off or I am incorrect on may others put there 2 cents on.

Thanks Ron, I will check it out.