Why Does My Olds 98 Has High Idle Then Hops And Jumps Wheni Step On Gas?

That sounds like a timing problem. Im almost certain thats what you will find to be the problem. See if the distributer cap is loose by attempting to turn it by hand. If its loose then you have found the problem. Turn it to where it idles correctly and tighten the bolts holding it down tight. If its not loose, go ahead and loosen the bolts and see if the idle smooths out by turning it. Note that if its not already loose you may be in need of a new coil or coil wire. This is a strong posibility since no spark acts like no gas. And you said sometimes it runs fine and sometimes not. It could be the coil sending a poor spark to the distributer or a bad wire that is having trouble making a good solid connection at one end or the other. But first check for a loose distributer as engine vibration could simpley be causing it to swivel throwing it out of time intermittenly.

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[automotive mechanic and phone modding enthusiast]