Wierd ignition problem (long)

4.0L, HO, 93'

Last Summer, I had a heck of a time trying to figure out an intermiten igniton problem. After getting the engine warmed up, like driving to a store and then coming back after 20min or so, I could not get it started. Only after lifting the hood and waiting 10-20 min is when it would then start agian. I had fuel, but no spark everytime this would happen. I then R&R'd all the important sensors, the coil and distributor cap.

Well needless to say either because of weather or that I found the particular sensor I haven't had a problem until yesterday. Well I did the standard diagnosis, unplug CPS, check fuel. No start. Then I started looking at the vacuum lines on the manifold and of course some are dry rotted and need replacing. Well I removed the line that goes to the MAP, and it started, It sounded kinda rough until I put the vacuum line back in, but kept running and got me home. This morning it got me to work just fine, and this evening I'll be replacing some lines.

I don't know if this is an actual ? or just sharing information about HO diagnosis. If anyone else has any ideas, because this problem is a royal PITA. TIA

Did you reset your computer recently?

Dunno if this is related, but mine ('92, 4.0 HO) acts that way when I reset the computer. I had to power down to replace a gauge, and the beast acted finicky for a couple of days afterward. That's happened twice now, I disco'd the battery again last week and it would start cold just fine, starting warm was a PIA. It fixed itself, and I wrote it off to data collection. Trouble codes haven't reported anything except the recent reset.

hth

I know I had did a computer reset last year. When I removed the vacuum line, I may have put the computer in a safe mode and then recovered when I put the vacuum line back on. Well like I said, I'll fix all my vacuum lines and see what happens. Next time I'll record the actual computer codes.

I have had it act up on me, and I simply turn it off and then turn it back on. The slight miss goes away, and this is a rare occurance.

Thanks Tucker