rough spot at idle

[seabee mike]

i have a 86 blazer with the 6.2 it has 56k on it and looks new. it starts great (most of the time) and runs strong with no smoke and no blow by. it gets 22mpg i have added some fuel cleaner/conditioner to it when i first got it from the army. (2 months ago) it has started up great every time except 3 times . it starts up fine then dies like it is under strain , i will have to crank it and give it a little fuel for about 10 sec. it will start to come to life and get better as it warms up (note i am in ca it is 40 to 50* out in the AM.)
Now it idles a little rough not bad but it does have rough spot as it will shake the truck every second or so. but as soon as you give it gas/fuel it is gone , very strong. any ideas? i have done a search but nothing i found had same symptoms

[dieselbegreat]

Check the fuel line connections from the tank to the fuel lift pump on the engine block. Any wet spots or stains that show leakage is no good. Check carefully over the rear axle area along the frame. Make sure the clamps are dry, snug and not deformed. Even a tiny pinhole will allow air to get sucked in overnight which causes the engine to die after first starting. Sometimes an air leak at the throttle shaft will cause fuel drainback, but the new style lift pumps have an anti-drainback valve that helps prevent it.

[jonflies]

There are other threads in the near past, indicating old filters, bad lift pump or bad timing. Personally, I've had plugged filters and bad lift pump, which showed the same indications.

[seabee mike]

thank you both. i did as you said and checked all the fuel lines and sure enough a small line near the filter?6 inches long. was leaking fuel when it sat. i was able to swap it out and it runs fine now. thank you again. mike