My Mark is dying, why.

[MachVIII]

Well I let my car sit for like 3 days without starting it last week. I go to start it up and it starts running rough, like barely idling. I give a little gas and I can hear something rattling around in the exhaust. Almost sounded like ice was in there and it broke apart and was flying through the exhaust. So I let it run for a little bit. I then go to drive it and take off and it looses power and eventually it will only run if I dont touch the gas. It seemed like maybe the coil blew out because it felt like it wasn't running on all cylinders. But because of that exhaust sound/issue, is it possible something happened to my cat that would make it do this. Could it be "clogged" or something??


Thanks, Ryan

 

[jeffbaze]

sounds like a cat problem to me

 

[MachVIII]

sounds like a cat problem to me

Are you just saying that, or do you have some reason/experience where you have heard of this happening.

 

[The Rev]

i had the same problem minus the exhaust issue. I ended up replacing the plugs, which made it fine and 2 days later the alt died.

 

[MachVIII]

i had the same problem minus the exhaust issue. I ended up replacing the plugs, which made it fine and 2 days later the alt died.

Did it just start doing it all of a sudden?

 

[MachVIII]

Update. Went outside to maybe see if I could unbolt the cat, no luck. Of course the friggin bolts are fused. Now it doesn't even really run either. tried to start it and it idled very roughly for about 10 seconds then cut out. Is it even possible that this could be an exhaust problem or is most likely electrical. Im gonna have to have it towed somewhere if I cant figure it out soon. Any help would be great!!!

 

[The Rev]

It ran like crap before, so I added Marvell Mystery Oil to my crankcase and it made it even worse. My plugs were fouled. But reason why it was running crappy was because the car had sat for 2 1/2 years before I started it. The plugs were replaced, wires as well. I ran a seafoam treatment, changed the oil and it ran like a champ for 2 days until the alt. died. Depending on your mileage you may need plugs and wires anyway so it wouldn't be wasted money. But when you say that it idles fine then when you go to pull off it dies, really scares me. I don't know much about cars (19 and this is my first) but I've read tons so I'm learning, someone will definitely chirp in on how to test your alt and what not. Also, bring it to autozone/advance whatever they can test your alt and pull codes I believe

 

[MachVIII]

I know its not my alt. I just replaced it. Im gonna have to try the plugs.

 

[unity]

Can you test fuel pressure? When the 4.6L "bottoms out" it can sound REALLY bad and may resonate into the exhaust. I have had that happen. Hard to explain.

Other things: Blown spark plug. Could also be the Idle Air Control Valve (IAC) or the TSP = Throttle Position Sensor.

Checking to make sure spark plugs are in place is the easiest, but check fuel pressure if you can. From there move onto the IAC. I do not know your year, but 93 to 96 the IAC is a pain to replace. 97 & 98 are a walk in the park, 10 minute job - max.