Sick 3.1 Cutlass, rough idle

[hermannm]

I was recently driving back on a road trip when the car had a sudden loss of power. It would maintain its speed at low idle but any time you tried to accerate it would start to surge. I pulled over a few times and put it in netral and reved it up a few times. It would go to about 4,000 rpm but stop there about 1,000 rpm short of the redline.

 

I managed to limp it home by feathering the throttle to gain speed and momentum. I tried replacing the ICM and coil packs, spark plug wires and fuel filter today. It still runs rough at idle. It seems to start fine idle for about 10 seconds and then go into a rough idle, where the car sputters and surges.

 

Any ideas what this could be?

 

Thanks,

 

Matt

[urbex]

IAC?

Edited June 19, 2011 by urbex

[RobertISaar]

a 4K rev limiter is in place whenever you're in park or in neutral but not moving, so that's normal.

 

any SES light? and you mention plug wires, but what about the plugs themselves? brand/age?

[AL]

Since its not missing at first but it doesnt after a few seconds makes me wonder if the 02 isnt giving off weird readings

[hermannm]

Ya I thought about the O2 sensor as well. I guess I forgot to mention the car is a 1992 3.1 not the 3100. The check engine light is not on. There was water and carbon splattered on the garage floor. The plugs are only about a year old. I checked a few of the plugs and they looked alright.

[szczur]

If it idles somewhat but cannot drive at all (sputters), it sounds like my problem of a worn out fuel pump (or fuel pressure regulator). Check your fuel pressure. It won't throw a code.

[hermannm]

Thanks for the help everyone. It was a failing fuel pump. Only 10 psi of pressure at the rail, enough for it to just barely run...