help*** new manifold, now car runs terrible
12-29-2009, 07:03 PM
#1
Thread Starter
Join Date: Dec 2009
Location: ok
Posts: 1
help*** new manifold, now car runs terrible
2003 mustang gt 5 spd
I replaced the plastic manifold with a new one last night and here are my symptoms:
the bad:
1. When starting from cold the car runs fine until warmed up.
2. Once warmed up, it idles rough and has a miss.
3. Car has a loss of power and bogs as you accelerate.
4. If you feather the throttle it will accelerate better, if you mash the throttle, the back will bog pretty bad.
Things I tested/checked:
1. I used my smoke machine to test for manifold leaks and there are no vacuum leaks.
2. No water in the spark plug tubes.
3. Everything is hooked back up.
4. I taped the EGR and the IAC and the idle changed slightly.
5. My Genisys Scanner detected a misfire on cylinders 5 and 8, so I swapped coil packs on those and still does it, BUT NO check engine light.
6. All fluid levels are good.
7. I have unplugged every injector and coil one at a atime and it changed the idle.
I am at my wits end, please help.
I replaced the plastic manifold with a new one last night and here are my symptoms:
the bad:
1. When starting from cold the car runs fine until warmed up.
2. Once warmed up, it idles rough and has a miss.
3. Car has a loss of power and bogs as you accelerate.
4. If you feather the throttle it will accelerate better, if you mash the throttle, the back will bog pretty bad.
Things I tested/checked:
1. I used my smoke machine to test for manifold leaks and there are no vacuum leaks.
2. No water in the spark plug tubes.
3. Everything is hooked back up.
4. I taped the EGR and the IAC and the idle changed slightly.
5. My Genisys Scanner detected a misfire on cylinders 5 and 8, so I swapped coil packs on those and still does it, BUT NO check engine light.
6. All fluid levels are good.
7. I have unplugged every injector and coil one at a atime and it changed the idle.
I am at my wits end, please help.
12-29-2009, 07:32 PM
#3
2nd Gear Member
Join Date: Jul 2007
Location: GA
Posts: 187
2003 mustang gt 5 spd
I replaced the plastic manifold with a new one last night and here are my symptoms:
the bad:
1. When starting from cold the car runs fine until warmed up.
2. Once warmed up, it idles rough and has a miss.
3. Car has a loss of power and bogs as you accelerate.
4. If you feather the throttle it will accelerate better, if you mash the throttle, the back will bog pretty bad.
Things I tested/checked:
1. I used my smoke machine to test for manifold leaks and there are no vacuum leaks.
2. No water in the spark plug tubes.
3. Everything is hooked back up.
4. I taped the EGR and the IAC and the idle changed slightly.
5. My Genisys Scanner detected a misfire on cylinders 5 and 8, so I swapped coil packs on those and still does it, BUT NO check engine light.
6. All fluid levels are good.
7. I have unplugged every injector and coil one at a atime and it changed the idle.
I am at my wits end, please help.
I replaced the plastic manifold with a new one last night and here are my symptoms:
the bad:
1. When starting from cold the car runs fine until warmed up.
2. Once warmed up, it idles rough and has a miss.
3. Car has a loss of power and bogs as you accelerate.
4. If you feather the throttle it will accelerate better, if you mash the throttle, the back will bog pretty bad.
Things I tested/checked:
1. I used my smoke machine to test for manifold leaks and there are no vacuum leaks.
2. No water in the spark plug tubes.
3. Everything is hooked back up.
4. I taped the EGR and the IAC and the idle changed slightly.
5. My Genisys Scanner detected a misfire on cylinders 5 and 8, so I swapped coil packs on those and still does it, BUT NO check engine light.
6. All fluid levels are good.
7. I have unplugged every injector and coil one at a atime and it changed the idle.
I am at my wits end, please help.
12-29-2009, 09:19 PM
#4
5th Gear Member
Join Date: Sep 2009
Location: KY, was MA
Posts: 2,797
i would take a guess at something like ignition related. on my 95 mark 8 i replaed a manifold and turns out i has 2 spark plug wires switched and it was doing the same thing you describe.
double check all is where it should be, if so then look into park plugs?
double check all is where it should be, if so then look into park plugs?
12-29-2009, 09:40 PM
#5
4th Gear Member
Join Date: May 2009
Location: DFW, TX
Posts: 1,925
I am going with bad coils too. They have a tendency to be touchy.
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