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rough idle/ rpm drop

601 Views 2 Replies 3 Participants Last post by  jwernatl
I have a 92 5.0 lx and it's been running very rough for a while now. it starts right up but almost stalls if i dont give it gas for a few minutes for it to warm up. It also idled very rough and occasionally would almost stall out at lights until I cleaned the IACV. That seemed to solve the rough idle problem for a few days, but today i was in a drive through and it started idling a little rough and suddenly dropped to about 300 rpms and almost stalled. I drove home but the whole way it was kind of sputtering and wasn't running right. I am not very mechanically experienced, so i was wondering if anybody has any suggestions. Help would be very much appreciated. Sorry if it's a little vague, i don't really know enough to fully explain everything.
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Looks like the IAC valve was not the main reason for the rough idle. Check for Diagnostic Trouble Codes (DTS). Check also the TPS voltage and for vacuum leaks.
I had the idle surge & lots of it.Sometimes it was to the point of wanting to stall the 5.0. soooo, - I cleaned the IAC and the MASS AIR - It helped wonderfully for a few days & then went back to the surging alot. SO, I replaced the IAC & after that it helped MUCHO. But it didnt stop it all together.

Now, It surges only a small % of the time. So I'm pretty sure it's the MASS AIR. Check that.

Also do you have you MASS AIR calibrated with your injectors? Kinda simple question but It's a thought.

I hope this helps.
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