The other day I went to start my truck(130,000 miles) 5.4 2004 and it cranked over and popped I assume throughe the intake and there Was a little black smoke from under the hood and it smelled like burnt carbon. I didnt attempt to start again until 3 hrs later and it popped right off and ran except the Idle now stays up near 1200 for a while and will reduce to 800 then 600. Once it gets below 800 it starts running rough and will stahl at times. Give it a little gas and it clears up until the idle comes back down.

A little history here. I have replaced plugs already about 3 years ago. I pulled the VCT’s today to look for obstructions lodged in them. I’ve also replaced the FPDM. I cleaned the throttle body and the MAF with cleaner. I get NO engine light. I drove it around The block a few times today and it seems to lack power now also. In the past once in a blue moon when you would try to start it back up after running into a store quick it would crank and act like it wants to start and it would die then it would take a few tries to get it to start, sometimes leave it sit and try a few minutes later and it would start. And that is what it did this time except it popped through the intake I assume.

Any ideas would be helpful.

Thanks!!

Well the plugs have 15,000 miles on them. I only drive this truck about 5000 miles a year. Is there an app for IPhones?

Well after some research I read a fellow member had a backfire once and it popped a vacuum line of the intake between the firewall and the intake. Got the ole inspection camera out an low and behold there it was. After a few attempts and son injunitity I was able to get it back on. Runs like a champ again.