Engine missing at idle

429ragtop · 06-20-2009

Have a SLIGHT miss during idle, idle is also a little rough. Any suggestions?.

429, edelbrock performer carb, cam (hydraulic), lifters. 60 over, fresh rebuild, runs strong higher rpm. No backfire, etc.

93ksstang · 06-20-2009

sounds like you have to much timing but not alot try backing it off just a little and see if that helps any.

Print Dad · 06-20-2009

Hello,
Try the simple stuff first.
1. - Check fuel filter
2. - Dirty air cleaner
3.- Idle adjustments

Then check wires, plugs, cap etc.
I find many times it is just a little thing that causes grief.
How is the gas? - Try a bottle of carb cleaner.

Just a few small ideas.......Print Dad

PaulS · 06-20-2009

I am with PrintDad here. Check your tune before anything else. Idle mixture and plug gaps. Check the choke settings and the timing. It doesn't sound like a fuel problem because under a load it improves. It could be a valve adjustment problem as they tend to disappear with speed as well.

429ragtop · 06-20-2009

Thanks guy's I appreciate it. I hooked up the vacuum gauge and was surprised to see a very slight but rapid flickering needle at idle. Stayed slight rapid flickering as rpm rose. Have a reading of 19 at idle, Im thinking I may have a problem in the ignition system somewhere? Running about 10 deg btdc. Very slight but rapid flickering needle, does not even drop a point.. Ignition?

429ragtop · 06-23-2009

com on people, dont leave me now

Print Dad · 06-23-2009

Quote:

Originally Posted by 429ragtop

com on people, dont leave me now

Hello 429ragtop,
Can;t help much more because I never used a avc guage but I did find the following link

How to diagnose your Ford engine using a vacuum gauge

Maybe something here will help a little.
That's about all I got...sorry Print Dad

429ragtop · 07-03-2009

Had a vacuum leak in the power brake booster diafram. All good now