super rough idle

I need some help from the experts please! I wen't to work today driving normal and when I got to work I parked and shut the engine off. The truck set for 5 hours before I started it for lunch but now the damn thing idles rough and I got a MAP code. I cleared the code and let it idle for about 10 minutes hoping it would either code again or start idling normal. While I was looking at everything under the hood I put my hand on the intake plenum and the 3rd runner from the throttle body was pretty damn hot compared to the rest. I said shit, I must have broke a valve spring or a valve is stuck. I pulled the valve covers off in the parking lot and everything still looks like new, nothing is broke or seams to be bent. I put everything back together and cranked it up and it idled normal for almost a minute before crapping out again.

Here's a little bit of log info at idle:
RPM - 919
Inector duty - 3%
MAF - 1.51
MAP - 60
Timing - 14.0
TPS - 0 %
Injector B1 - 4.5
Injector B2 - 4.3
O2 B1 - 217
O2 B2 - 846
LT B1 - Peg out at 25
LT B2 - Peg out at 25
ST B1 - 0
ST B2 - 1.6

Any thoughts on this?

Greg, Would you move this to the tuning section. I wasn't thinking when I posted it.

Try that plug on that cylinder, other than that if the code doesnt come back then you know its probably not the MAP sensor. I would also check the wire for that cylinder.

I'm with you on the sensor chris. I know for sure that the coils are working but didn't have the tools to pull the plugs today. I'll try to pull them tomorrow just to see if they're wasted. I need to buy a set for the new heads when they came in anyway.

I'd move it but for some reason I have no magical powers in this region. I am but a meek little mortal here. :cry:

Readheart, dont lie to us, we know u r a highlander (inmortal) that's where ur knowledge come from!!!!!!!

I se the log and Bank one show lean mix!!!!! and bank 2 too rich, I think that for a idle 400-600 will be a nice number.

I'll check the plugs and the O2 sensors if I was u!

Also fuel filter and probably dirty injectors, but the cycle looks good and steady.

Can't tell more, that is all a I might learn thru Allen Voodoo

Did you get a bad batch of gasoline? I'd take your return line off your fuel rail and pump gas into a clear container and see if you got water or contaminants in it.

Ok, here's the scoop:

Clean fuel 100 plus octane added.
Clean fuel filter
Plugs are clean but I'm going to put a set of TR6's in with the new heads next week.
Clean injectors. I have a 3M cleaning kit.
Compression test 145 + on all cylinders.

Still the same problem. Act's like the timing is off. I'll figure it out this weekend.

Could you possibly have a coil dying? Losing fuel pressure? Low voltage?

It's possible, but what would heat just one intake runner on the plastic plenum? That's what has me thinking an intake valve is possibly sticking once the engine gets moving and friction takes over. I know when a valve leaks it will force gases back into the intake pressuring it up. I do get a MAP sensor code saying it's out of range on the Solaris. I don't get it.

Do you have access to one of the new laser pyrometers? Once it start missing I'd hit all the intake runners and exhuast ports to check for variance.

Tore the heads off today and found a bad valve spring. The funny thing is the valve would open and close somewhat normal. So much more Manley springs, they suck in my opinion!! I'm giving the Patriot duals a try now with the 243's. The Taylor wires are giving me hell also. Hopefully I'll have everything back together tomorrow to see how it's going to run. I new there was an intake valve problem with a hot intake runner, everything looked good until I finally had time to pull the springs out.

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Tore the heads off today and found a bad valve spring. The funny thing is the valve would open and close somewhat normal. So much more Manley springs, they suck in my opinion&#33;&#33; I&#39;m giving the Patriot duals a try now with the 243&#39;s. The Taylor wires are giving me hell also. Hopefully I&#39;ll have everything back together tomorrow to see how it&#39;s going to run. I new there was an intake valve problem with a hot intake runner, everything looked good until I finally had time to pull the springs out.
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Good Post. I learned something new about sticking valves.

I&#39;ve run the Manleys without any issues. I&#39;ve also run the Patriots without issue, but like you there are numerous posts on LS1Tech about Patriot Gold failures (even so far as parts of the springs falling off and being pulled out of the oil pan on the magnet). I think Gunnar sells a platinum series spring, not sure what the difference is.