Running like crap after disuse

[widebody911]

I haven't been driving my 911 much lately. I drove it to a show/swap back in October, and before that I hadn't driven it since July or so when I smogged it. As a result, it's all buggered up.

The primary symptom is a heavy miss anywhere past half-throttle. If I try to go WOT, it feels like the rev limiter is kicking in. When accelerating part-throttle, the new rev limiter kicks in around 5000 RPM, although it's not consistent. It's a little rough at idle as well.

Any suggestions apart from fresh gas (done) and techron (done)? I'm tempted to just replace the injectors outright, but I wonder if there could be something else funked up that I should look at. Plugs? They're not that old, and I didn't think that storage would foul them.

I haven't been to the track in over a year, and I signed up for an event on 4/16 @ Thunderhill. In an attempt to shake out some of the cobwebs, I drove it to work today. That's John Birkett's M491 parked next to me.

[DW SD]

any chance your fuel filter is plugged? I had a similar problem with mine. I had fibers from the inside of the fuel cell plugging my filter (I added a filter prior to the fuel pump).

When it became more acute, my car would die for a few moments following a heavy application of throttle. The pump would have to catch up on the fuel pressure, I believe.

My filter is an Earl's. I cleaned the screen on two occassions and the problem went away immediately.

Techron would not have solved my problem.

Doug

[randywebb]

Thom - I was going to say plugs - but you already did.


I'd first "floor it!" - try some high speed running and see if it clears up - the Italian tune-up is often helpful and usually fun.

You can try it cruising right at 5k, then see if you can run it a little higher.

If not plugs (or do you have mech. points?), then it is time to think about what could have happened in storage - i.e. animals chewing on electrical wires, debris falling into the wrong hole, etc.

I had a similar issue and it was the plugs - they loaded up superfast on my carbed motor - twin-plugging notwithstanding.

Good Luck!

[widebody911]

On the drive home from work yesterday, the car improved significantly, although it's still maybe 75% of 'perfect'

I think I'll go ahead and order up a fuel filter and a set of plugs, just to be on the safe side.

[nineoneone]

I might check the distributor for moisture, as they set-up condensate may form under cap.

[patkeefe]

Moisture is my guess #1. My old farmer's adage of "90% of the time, it's a fuel delivery problem" doesn't apply well to 911's, I have come to find out.

[Chuck Moreland]

I go by the adage that most fuel problems are found in the ignition. After you've been through the ignition twice and ruled that out as a problem, go through it again to figure out what you missed.

That said, I would change the fuel filter.

[bigchillcar]

chuck +1