2001 4.0 coughs on cold start, and then starts fine....

Ok, it's kinda hard to describe the sound, but it's kinda like a cough or hiccup. The motor will crank once, cough, die, then I try again and it fires fine and runs without a problem. I'm really due for a spark plug change and was wondering if this might be the cause(gonna do them tomorrow). Any insight fellas? Thanks

Ary

P.S. 54k miles on Jeep, serviced regularly('cept plugs, just can't seem to get around to them, til tomorrow)

Very odd problem-

That is a most unusual drivability problem!! Sounds like the fuel pressure is not staying up as it should be maybe. Does black smoke come out of the exhaust when it does start? I am wondering if an injector is leaking down into a cylinder causing low fuel pressure at first start. With those miles could totally be the plugs, however. I would recommend stock Champions at stock gap. Best overall results that way. Could try a good 'ole bottle of Techron to see if that may help if does happen to be an injector malfunction....

My 2000 has done the exact same thing. When I would crank it to start it would make that coughing sound, and then sometimes when it started after making the noise it ran rough for like 3 secs and then smoothed out. I took it to DC when it was still under warranty, but of course it wouldn't do it again, and the said it hadn't thrown any codes. It has been several months since it has done that. I hope the gremlin causing it got lost when I moved to my new house.

Just to eliminate any confusion, the truck does not start and then die, it cranks, coughs, and then when I go to crank it again, fires right up. I went out of town for 3 days last week, and when I came back it was doing this, however, I also noticed that it was running slightly cooler in general and accelerating better(seat of the pants). So I'm not really sure what's going on. I bought a set of autolites, should I go buy some champions(store that I went to didn't have champions) and what is the stock gap? Thanks

Ary

Champions, yes-

LOL funny how different parts of the country are loyal to different parts. Around here you have a hard time finding champions unless it is for a lawnmower. BTW that is exactly what happens with my 2000. I don't know if it will start when it makes that coughing sound, because it always startles me so I let off the key. When I go to turn it over again it fires right away, sometimes stumbling for a sec and then smooths out and runs great.