starts fine, smooth idle 30secs, rough idle, then dies

Please tell us whether this is a Chevy 454, Ford 460 or other.

Water in the fuel tank. Idle solenoid bad are the first two things that come to mind. It is also quite possible that there is electrical issues. Such as plug wires have broken down and are shorting to ground instead of through the plugs. There are literally dozens of possible causes and it will take a lot of time and patience to track them all down until you find the culprit.

It is a Chevy 454 engine.

Thanks, I'll let my husband know.

april10, We had a similar problem with our Bounder, it was the spark plug wires. OEM wires lasted a long time while the replacement set died quickly. Replaced twice under the shops warranty. Cost of wires was about 150 bucks.

Same symptoms on a GM SUV - it was a carboned up EGR valve. DH took it off, blew the carbon out and we repeated this about every 6 months. The valve worked like it should except got all carboned up. Is there an EGR valve on a coach?

When this happened, by the time it progressed to not running my check engine light was usually on.

D.E.Bishop wrote:
april10, We had a similar problem with our Bounder, it was the spark plug wires. OEM wires lasted a long time while the replacement set died quickly. Replaced twice under the shops warranty. Cost of wires was about 150 bucks.

I can't imagine how bad plug wires would allow it to start and run fine for a short time then quit. It sure sounds much more like a fuel problem though its possible that if it has the electronic ignition that it is failing but I will still say most likely it fuel related.

Question : when it quits, how long before it will start again?

Yeah, sounds like fuel delivery and specifically after the cold start period. If you give it gas to put it above idle, will it still die after those 30 second? Also, if it has died and you start it again, will it run for a while and die again or does it not run at all?

The EGR is usually activated at cruising speeds and shouldn't affect idle speed but you can remove the vacuum line to it to see if that stops the problem.

I am guessing fuel filter.. but that is a guess.

Depending on the fuel pump location (Tank or engine) it might be a religious fuel line as well (It got holy) and letting air into the system reducing pump effiency. This is not possible with a tank mounted pump.

april10 wrote:
We have a 1990 Southwind motorhome. Ran fine until recently. Now, it starts right up, runs good for about 30 sec., then the idle gets rough, the motor sounds like it's surging, and it dies. My husband cleaned out the fuel filter (there's only one) but its not the problem. Any suggestions would be greatly appreciated! Thanks!.

Need to replace the fuel filter not clean it. Did he replace the air filter? He may have two fuel filters, one on the chassis rail and another on the carb/EFI fuel inlet.