Ironman is acting funny

Tags: rough idle, lunging, coils

So over the past few days I've been driving my truck more. It's started to idle kinda funny. Think big block chevy with a wild street cam. Real lopey. At the same time, as it comes to a stop it kinda lunges forward when you complete the stop and sit for about 2 seconds. It also has a tendency to lunge forward when you put it in D when cold, but never in reverse and never when warm.

So here's the breakdown:
320k miles
Trans juice is clean and pink, spill and fill 2 years/2k miles ago.
Last oil change 2 years/2k miles ago.
No codes, did show p4010 or whatever that evap code is. Hasn't shown itself in awhile.
Maf and TB cleaned about 2 years/2k miles ago.
Plugs changed 2 years/2k miles ago.

I did see some coils starting to crack while doing my VC gaskets when I pulled them. I don't think they would cause this insane idle I have going on, but I could be wrong. I don't want to fork out $400 for new coils just yet...

 

Throttle cable adjusted correctly/Slack taken up?
PCV valve?

 

Added TB cleaned to OP. As far as I'm aware these are all electronic throttle?

 

The early trucks were drive by wire. I know there is some slack I can take up from crackie, and did the same on the V6. Need nickname for that one...

 

I don't think that would have an effect on idle, but I can check it. I do have a FSM laying around here somewhere...

So you need a name for the v6 truck eh? Friday is coming up....

 

Should be two 14mm jamb nuts on the throttle cable.

 

Thank Bubba!

 

Dammit Noah, you made me go and find them. @Sirfive

 

There's a digital version above that you can search key words on.

 

Dude, I'm old. Digital shit is for you youngsters. I prefer paper.

 

I don't have time for paper! LOL

 

Honestly, I'd check your coils first. Do you still have a DMM? What about the Air filter?

 

Did you just ask an electrician if he has a DMM? I suppose I can check them. Filter was about 4 yeas/4k miles ago.

 

How long has the truck sat? Or fine one day, lumpy the next?

Is it rhythmic, like a dead cylinder? Or loading where it almost dies, then speeds up, repeat?

when it lunges is it because an engine rpm jump?

everything is suspect on a 320k engine.

Hit each manifold port with a laser thermometer right after startup make sure they’re all getting warm evenly. Check fuel pressure.

 

Sounds like fuel pump to me. Check the fuel pressure at the rail and watch for bleed-off, if there is any. Malfunctioning coils wouldn't cause lunging/surging.

 

More on this same idea. Leaky injectors?

 

Poor idle is often vacuum related. Won't throw codes. Check all you vacuum line connections and hoses. May have a leak.

 

Truck sits for a week at a time, though it's gonna be a DD now. It's been progressively getting worse. It's definitely not rhythmic, and it does go up and down, but not much. The tach doesn't even register it.

There's no fuel around the injectors or fuel smell.

I'm leaning towards this. I popped the hood when I got home a while ago and snapped some pics.












I did notice oil around my PCV valve, even though I cleaned my VCs when I did that gasket job. It's sitting at a funny angle too. I can also hear what sounds like a vacuum leak from under the intake, but iirc there's no lines under there, and I torqued it down to spec when I put it back on.


Also, we were talking about clean engine bays the other day. Yeah.....

 

A can of carb cleaner should help track down a vacuum leak. Spray around where you hear the hissing, if it is a vacuum leak the rpms will increase when the leak pulls in the carb spray.

 

Nice comforter

 

I know, I know. I'll get to it. It was like 95 this weekend then rained most of today.

I would lie and say it's my boy's, but yeah, it's mine.

 

New vacuum hoses ordered thanks to @Tundra2. Ordered the kit he recommended that has an assortment of sizes in various lengths.

 

Didja try to suck&blow any of the ports on that evap box thing?

 

Yeah, like, maybe when it was all hot and wet, like last weekend? Nothing like a good suck&blow when it's hot and wet. On your Ironman.

BTW, you get off your ass and replace that SHO t-stat yet?

 

(Did anyone else ever know boomhauer had a slant 6?)

a little grease should seal to get it running right if its just cracked hoses. Maybe the evap thing had some settling that fouled a seal or stuck a valve. I dont know, i do my best to try to remove as much emmision equipment as possible.







they exhaust valve actually is the bees’s knee’s, but the cable is sticky, so ive been working graphite and compressed air through it. This bike will wheelie in 3rd, where with it stuck open, thats a first gear only problem.

 

Well, last time I sucked a hose I got some nasty shit in my mouth. I ain't doing that again.

 

Be gentle, you’re not trying to get it to marry you, just looking for a little flow.

 

So after 3 weeks of no keys, I got a new one and jump started my truck. There's a nice hiss from what sounds like under the intake, and a popcorn making sound, almost like backfiring through the intake. I have new vac hose waiting to be replaced, but this sounds like more than that. I made a 41 second video of it.

https://youtu.be/NxYVy9Gntu8

 

That sounds like the timing is off.