"Puffing" Exhaust

[88XJSport]

I was in the hatch area of my xj the other day, and it was idling, and i noticed every 10 or so seconds i would get a noticeable puff sound from my exhaust. The engine didnt miss at all, just a big puff from the exhaust, and it happens every 10 or 15 seconds. I thought the engine was missing, but it wasnt so i am stumped here. Any help is great. Thanks.

[jeepdude10000]

must have some kind of restriction in the exaust.
it builds pressure the lets go, how good is ur cat?

[92DripCherokee]

might be sticky exhaust valves, a high mileage engine tends to get this from weak valve springs, and worn valve seats/faces.

[88XJSport]

Thanks for the help, it could be the valves, but i have a new cat with 9k on it.

[88XJSport]

Would seafoam in the crankcase help with sticking valves? Ive used it in the intake, and i have heard that it could be used in crankcase to do what? PS engine has 163,000 on it.

[IntrepidXJ]

mine does the same thing, and has for a while. even with a new cat. i haven't worried about it ;)

[swbooking]

mine gave out little puffs every once and a while too, it turned out there was a little cut in the spark plug cable and it was sparking against the engine block, i just put some RTV on it and no more puffs. I noticed it at night, i lifted the hood, and saw little flashes of light. Maybe check you wires...
-Allen

[88XJSport]

mine gave out little puffs every once and a while too, it turned out there was a little cut in the spark plug cable and it was sparking against the engine block, i just put some RTV on it and no more puffs. I noticed it at night, i lifted the hood, and saw little flashes of light. Maybe check you wires...
-Allen
Hey looking at spark plug cables is easy enough, maybe ill try that. Thanks!

[93RugbyXJ]

Mine smokes when the engine is hot and I’m idling at stoplights. Someone told me it might be the valve seats so I came here to look it up. How much would it run to get them replaced? Mine has 169K on it and is a 93 I6

[jeepdude10000]

Mine smokes when the engine is hot and I’m idling at stoplights. Someone told me it might be the valve seats so I came here to look it up. How much would it run to get them replaced? Mine has 169K on it and is a 93 I6

more likely "valve guides", but u got the idea

[93RugbyXJ]

so anybody know how much $$$ its going to run me, It sounds like its something I need to let a mechanic do.

[jeepdude10000]

so anybody know how much $$$ its going to run me, It sounds like its something I need to let a mechanic do.

it all depends what ur going to do , but since ur going that far, should just rebuild the whole head.

there is a way to check the guides without taking it apart, I will try to remember.:lickout:

[jeepdude10000]

here follow link to check engine problems with vacuum gauge.
http://projects.mergecomputer.com/ford%20tractors/Service%20Specifications/vacuum%20gauge%20diagnostic%20chart.jpg

[93RugbyXJ]

Thanks, but where do I get the tools and what do I do? I do moderate work to my truck, change oil, tranny fluid, install electronics and I have a basic idea but any info you could supply would be much appreciated.

[jeepdude10000]

all u need is a vacuum gauge, u can pick it up almost anywhere for around $15.00 , then just hook it up to a port on the intake, and bring engine upto operating temp and read vacuum gauge.