Anybody have any idea what to check on my 98 Cherokee, 4L I6, 105k miles? Symptoms: hesitates, especially at low speed (5-20 mph). Sometimes does the herky-jerky in idle right after starting. Symptoms seem to go away at higher speed or when engine is warm. I'm in Utah, so it's below freezing most of the time right now.
Thanks, Mike
snipped-for-privacy@yahoo.com did pass the time by typing:
Could be any number of things, failing coil, cracked plug, bad plug wires (If your model still has them). Clogged fuel filter, failing CPS sensor, etc.
Pull the codes and see if it's got anything in there.
We had a brand new cherokee (4.0L) in 2001 that had a rough idle first thing in the morning. Seems to just be a characteristic. I had the stealership look at it a couple of times (even had a plug go bad on me at about 15k miles). My 2000 we have now does the same thing when it's cold. Doesn't seem to be anything wrong, just a not-so-refined motor. Works like a charm. :-)
Eric
99 TJ SEThanks for the replies. I pulled the plugs out last night just to check (Bosch Platinums) and they look fine. After reading that some people didn't like them, I considered switching, but they look great and they've been fine for over a year. I'll see how it runs for a day or two, and if it doesn't go away, I guess I'll take it in. I'm no mechanic.
There are a couple plugs and sockets on the throttle body. Opening these and cleaning the pins with a spray contact cleaner or even WD40 can do wonders for cold idles. One is the TPS or throttle position sensor. Ours in an 88 and I need to clean it every couple years.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'ssnipped-for-privacy@yahoo.com wrote:
I've had some of the Bosch Platinums break down internally - no external sign of damage. They usually would misfire only under heavy load (slowly getting worse) and were not carboned up like you would expect from a bad plug. Almost impossible to diagnose. At least when the Champions fail, they fail completely so you can tell which is which.
I will third this opinion on spark plugs, I would recommend a "normal" plug. I've had good luck with normal Bosch plugs in other cars but only had good luck with Bosch Platinums in a VW. The other times that I personally tried them (until I wised up) I always eventually had misfire problems. Must be my selection of vehicles:) I've always had good luck with plain old Champions in Jeeps and other Chrysler vehicles.
Regarding hesitation when cold, I would recommend checking all the vacuum lines. When I checked them on my '93 GC last summer a bunch of them were hard and/or cracked. I replaced them all and my GC seemed to run better especially right after start up.
WB
Will H> On Sat, 15 Jan 2005 18:02:45 UTC snipped-for-privacy@yahoo.com wrote: >
?????
You talking about me? I think Bosch platinums are junk and have never seen a Jeep engine run well on them.
The last 1 year old set I tossed in the trash for someone did show signs of misfire though and still ran like crap when warmed up.
That is why I mentioned the TPS connection. It is more likely to give cold running issues I would think.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's"L.W.(ßill) Hughes III" wrote:
The plugs really do look good - nice and clean. I haven't had any problems with them since I put them in over a year ago.
I've taken the jeep around the block a few times in the last few days when it's cold, and it is running fine. I don't know what the deal was the other day. If it happens again, I'll take it in. Thanks for the replies.
Mike
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