idle surging after first drive since storage?

[JRS03]

Little background- 03 cobra, mods- VMP TVS, 2.8 pulley, 60lb injectors, budget return fuel system, cattless exhaust, PVC/EGR delete and the usuals. I haven't driven it since the dyno tune back in December. I took it out Friday to get some fuel. When you first start it up idles fine, when you drive it, it drives good. If you let it sit and idle for an extended amount of time after you drive it, the idle surges between 600-830 ? I have cleaned the IAC and nothing changes. I also noticed the fuel pressure on my areoforce usually stays around 50.2 at idle but after driving for awhile it will idle around 49.3ish? Also, when i start it and let it idle before i drive it, it will idle fine, it just does it after you drive it? Any advice or suggestions wiould be greatly appreciated.

 

[01Jes]

Have you removed the TB and cleaned it? I'd also reflash the tune. I had this issue before but after time and what I mentioned above it vanished. GL

 

[CtSvt]

Was your battery dead or disconnected ? Mines doing the same thing , its probably the computer trying to relearn everything again , it should go away after a few drive cycles

 

[oldmodman]

Also, check the vacuum line going to the bypass valve. An always closed bypass can in some engines cause an idle surge. Or if the return spring broke it could be cycling open/closed too.

 

[JRS03]

Was your battery dead or disconnected ? Mines doing the same thing , its probably the computer trying to relearn everything again , it should go away after a few drive cycles

Yep, the battery has been really low to the point I have had to put a trickle charger on it. Damn Optima.... Plus I've had the battery unhooked a few times over the winter.

 

[JRS03]

Also, check the vacuum line going to the bypass valve. An always closed bypass can in some engines cause an idle surge. Or if the return spring broke it could be cycling open/closed too.[/QUOTE

Vacuum lines are the first things that I checked, I Couldn't find any leaks. The TVS doesn't even have 100 miles on it yet so I know the bypass Is good, when you pull the vacuum hose off the bypass it acts funny plus it changes the sound of the blower when the vacuum is pulled and the bypass Closes. Im hoping that it will just work its self out.

 

[ninty9cobra]

Yep, the battery has been really low to the point I have had to put a trickle charger on it. Damn Optima.... Plus I've had the battery unhooked a few times over the winter.

Same thing happened to my bro's 03 cobra. Disconnect battery for a couple of minutes. Reconnect and drive around normally for about 50 mile till computer
learns parameters again.

 

[GoGreen04]

I've been having the same problem ever since I installed the budget return style kit. I'm almost positive that it's the fuel pressure. Mine at idle is around 45psi when it should be around 39-40. It was worse when my fuel pressure was higher. It also only surges bad after driving for a while. I also do not have an FRPS on my setup. Are you running a FRPS?

 

[JRS03]

I've been having the same problem ever since I installed the budget return style kit. I'm almost positive that it's the fuel pressure. Mine at idle is around 45psi when it should be around 39-40. It was worse when my fuel pressure was higher. It also only surges bad after driving for a while. I also do not have an FRPS on my setup. Are you running a FRPS?

Yea, Im still using the FRPS. My gauge on the regulator reads at 40psi at idle. My surging has went away after driving it the past 2 days