Dysturbed87 Posted April 27, 2015 Report Share Posted April 27, 2015 I am attempting to figure out the issue on my girlfriends car. Its an 03 GT and I've got a 00 GT so I can pull parts from that to check if a certain part is the issue. At first it would run, but the idle would bounce between 200-1800. Sometimes it would stall and other times it would be very very close to it (all lights appear on the dash like it had), but then it would rev back up to 1200-1800RPM. I never got video of it, but I found one on YouTube that his car is doing the same thing. http://youtu.be/czLoOKCG_wEAt first I was thinking it was the IAC, but all times I've seen an IAC go bad it starts and immediately stalls. The other reason I'm not thinking it is the IAC is because when you give it a little gas it is missing. I never got a code for any specific cylinder, but did get a P0316 (miss fire detected within the first 1000 RPMs). I pulled the plugs (motorcraft coppers) to see if there was an issue with them. They visually looked fine, I checked gap and it was within spec. I reinstalled them and now it won't stay running. It dies immediately after startup.I did pull my IAC and put it on hers and that didn't make a difference. My IAC is vented though and am not sure if they are interchangeable. I will be pulling plugs again and rechecking the gap and connections of the COPs since the car won't run after I pulled them. I also have used set of COPs and will swap them all when checking the plugs. Below is a video of what it does now.Things I have done:-Pulled plugs and checked gap-Cleaned MAF-Swapped IAC-Disconnected batteryAny suggestions would be appreciated. Link to comment Share on other sites More sharing options...
Blackmage Posted April 27, 2015 Report Share Posted April 27, 2015 possibly a really bad vacuum leak? any work done on the car before this started happening? is the JLT intake new? Link to comment Share on other sites More sharing options...
Dysturbed87 Posted April 27, 2015 Author Report Share Posted April 27, 2015 No work was done prior to the weird idle. I pulled the plugs to check them for any issues, there weren't any, and after I put them back in it just stalls. I plan to pull them again to regap and replace the COPs with some others that I have.JLT intake has been on for about 2 years. I am just lost as to where to start looking for a vacuum leak though Link to comment Share on other sites More sharing options...
Blackmage Posted April 27, 2015 Report Share Posted April 27, 2015 once it fires it sounds like it runs fine, but sounds like theres a vacuum leak. i wouldnt waste any more time on the plugs and COPs. Link to comment Share on other sites More sharing options...
Dysturbed87 Posted April 27, 2015 Author Report Share Posted April 27, 2015 When I unhooked the MAF it would stay running, but the same way it starts up. Rev high, drop to almost stall, rev high, almost stall, rev high, etc. Once I reconnected it, it just stalled Link to comment Share on other sites More sharing options...
Blackmage Posted April 27, 2015 Report Share Posted April 27, 2015 so the maf isn't reading the air coming into the motor correctly. if you want try switching the maf out. but it sounds like you have unmetered air entering the intake. Link to comment Share on other sites More sharing options...
Dysturbed87 Posted April 27, 2015 Author Report Share Posted April 27, 2015 I'll see if I can find a vacuum leak tonight.Do you happen to know if a 02-06 crown vic/grand marquise/f150 MAF would work on the mustang. I know I can't use mine because the IAT is separate from the MAF. I know the pull a part has a bunch of crown vics/grand marquise/f150s there Sent from my DROID RAZR using Tapatalk Link to comment Share on other sites More sharing options...
Blackmage Posted April 27, 2015 Report Share Posted April 27, 2015 from the looks of it on rockauto, yea a lot of them are interchangeable. take a pic of the MAF on her car and just cross reference it while your at the pick n pull Link to comment Share on other sites More sharing options...
Dysturbed87 Posted April 27, 2015 Author Report Share Posted April 27, 2015 It is probably best to take it with me. I appreciate all the help.I looked at rock auto to see what other models/years work with it, but realized their list was wrong when it listed it working on all 99-04 Mustangs.Sent from my DROID RAZR using Tapatalk Link to comment Share on other sites More sharing options...
Blackmage Posted April 27, 2015 Report Share Posted April 27, 2015 yea but if you check the non OEM one, they have it broken out for just the 03-04 GT and then they have the other models listed too. Link to comment Share on other sites More sharing options...
Dysturbed87 Posted April 27, 2015 Author Report Share Posted April 27, 2015 Ok, well my retarded self left the PCV hose off after messing with the plugs. So now the car will stay on (mostly), but is back to acting like the first video I posted.The below video is the my girlfriends car. It still sounds like there is a vacuum leak? I checked all the hoses and connections and cannot find any places that are cracked or not connected.https://youtu.be/dxpOfx6fvKQ Link to comment Share on other sites More sharing options...
Blackmage Posted April 27, 2015 Report Share Posted April 27, 2015 Ha it's all good. We all make mistakes.And wow that kinda sounds like the iac is blowing off after it nearly stalls. I would try an iac that's made for that car and give it a whirl. Sent from my iPhabletI wonder if the gasket for the iac isn't shot tooSent from my iPhablet Link to comment Share on other sites More sharing options...
Dysturbed87 Posted April 27, 2015 Author Report Share Posted April 27, 2015 I am at the parts store, so I will be getting a gasket and some throttle body cleaner. Hopefully that will hold it over until I can get a motorcraft one I appreciate all the helpSent from my DROID RAZR using Tapatalk Link to comment Share on other sites More sharing options...
Dysturbed87 Posted April 28, 2015 Author Report Share Posted April 28, 2015 Cleaned the IAC. It stays running and idles at 480-500 RPM. With that a new IAC will be ordered. Anyone have a preference on brand? I know that Hitachi is an OEM, but I think there's is vented and the ones for 03-04 are non vented and I believe denso is the OEM, but I can't find their stuff anywhere. Thoughts on brands though?Sent from my Nexus 7 using Tapatalk Link to comment Share on other sites More sharing options...
Blackmage Posted April 28, 2015 Report Share Posted April 28, 2015 I've always had oem IACs so I couldn't really tell ya thereSent from my iPhablet Link to comment Share on other sites More sharing options...
SniveTroll Posted May 26, 2015 Report Share Posted May 26, 2015 i dont care what brand as it works. i usually get them from a yard. Link to comment Share on other sites More sharing options...
Dysturbed87 Posted May 26, 2015 Author Report Share Posted May 26, 2015 I should mention that the IAC fixed the issue. I just had her buy a motorcraft from rock auto. Still have to go through and check for vacuum leaks since there might be one.Sent from my DROID RAZR using Tapatalk Link to comment Share on other sites More sharing options...
SniveTroll Posted May 27, 2015 Report Share Posted May 27, 2015 i think harbor freight sells a vacuum gun. well they use to. Link to comment Share on other sites More sharing options...
