Rough running after intake manifold replace

My husband and I changed the Intake Manifold on my 1998 gt 4.6. But after the install it ran like crap. :disappoin We cleaned the spark plug areas (advice from another owner) and it was a little better. But it still runs real rough at acceleration, no power. It seems to misfire at all speeds, but above 30 or so it sounds almost normal. Sort of like a lawn mower. The engine smells like sulfer but doesnt appear to leak or overheat any more.
We are at our wits end. :banghead: And dreading the trip to the mechanic :2cents: . Please... any advice at all would be greatly appreciated. :lol2:

Thank you,

Jennifer

DId your replace it with a stock manifold? Or the PI manifold? Why did you change it? Ford has recalled the manifold becasue of it cracking, and will replace or pay up to 750$ for shop charges for someone else to replace it.

oh and id say maybe a leak in the intake gasket?
You could have autozone run a diagnostic for free and that should help you at least narrow it down.

Good luck!

We replaced it with a non-'after market' part. Due to the defect it had been leaking. It had aluminum where the thermostat sits.

Will ford refund part costs if you do it yourself?

I am not sure if ford will do that, but with the rough idle it sounds like you may have a leak o one of your spark plugs or fuel injects could be out. All of that is around there and maybe you had accidentally knocked one out of place or something. I would talk to a local ford dealer and find out what they could do for you. In worse case scenario you could take it to a shop and have them hook it up to an electric computer to read the the codes and find out what exactly is wrong for the cost of $50 or $60 bucks. If you want them to do the work, a lot of shops will include that price into what you need done.

Hi Guys, My son has a 96 Mustang GT v8 w/Manual Trns. He had a H pipe put on with the dual exhaust. He installed the O2 by-pass kit to turn off the check engine light. The car ran great for a few months with no trouble. All of a sudden the car began to hesitate and feel a miss when going through the gears. It seems to do it under a load. He has changed the plugs, coil paks, wires and gas filter. He also tried disconnecting the sensor in the air hat and it ran even worse. He also tried disconnecting each injector while the car was running and there was a big difference in each cyclinder so it seems they're working. Anybody have any suggestions or had the same trouble? Thanks Alot JT

sounds like a leak to me... spray some carb/throttle body cleanear or even WD40 around where the intake meets everything, and if the motor picks up... u found ur leak...



My husband and I changed the Intake Manifold on my 1998 gt 4.6. But after the install it ran like crap. :disappoin We cleaned the spark plug areas (advice from another owner) and it was a little better. But it still runs real rough at acceleration, no power. It seems to misfire at all speeds, but above 30 or so it sounds almost normal. Sort of like a lawn mower. The engine smells like sulfer but doesnt appear to leak or overheat any more.
We are at our wits end. :banghead: And dreading the trip to the mechanic :2cents: . Please... any advice at all would be greatly appreciated. :lol2:

Thank you,

Jennifer