mudvayne1

I posted a thread the other day but I can't find it.

Here's the deal. My mustang runs just fine when it is idling but when I accelerate it starts sputtering like it is starving for gas. The guy that owned it before me said he had replaced plugs and plug wires like 2 weeks ago. The other night I started it up and I pulled the wire off the distributor cap and it was getting a weak arc to it so I changed the ignition coil. That didn't help the problem. I was thinking it could possibly be the fuel filter but I checked the plugs and they are black. Doesn't that indicate that there isn't enough fire burning the gas as it goes?

Help me out guys. What could it be? I wanna get this car up to its full potential because I haven't been able to open it up since I bought it.

mjr46

no that may indicate your running way to rich take it to a qualified tech!! there are too many variables to diagnose a problem like that but check fuel pressure. if it gets to much gas it'll spudder too!! is check engine light on??

mudvayne1

Check engine light only comes on when I try to gun it. I tried to get it checked with a computer but it wouldn't read it.

LTnone

Fuel filter would be a good thing to do anyway, but if it's running rich start by checking fuel pressure... with the line unhooked (and plugged with your finger), it should be at ~38psi. Are all of the plugs like that?

mudvayne1

Yes they are all like that.

mattdel

i'm bettin on a pressure regulator diaphram/vacuum line leak

mudvayne1

How much would that cost to fix? And by the way with this car having this problem it is still faster than my 3.8 ever was. I love it.

kilgorq

A Plugged catalytic converter can do that also. How is the flow of exhaust out the tailpipe.

mudvayne1

Not sure, I mean it sounds normal. It revs up just fine to about 3k rpms then it starts bogging down. It sounds awesome until it bogs.

mattdel

take the vacuum line off the regulator while its idling.
if there is nothing wrong with the vacuum source or the regulator, the idle will surge momentarily right as you take the line off.

if you dont get a surge, you found a problem.