This is the second time this has happened, otherwise the Jeep runs great. Once at about 15k miles and this time at about 50k miles, upon cold starting, the engine stumbles (of course no gas pedal), runs really rough for about 20-30 seconds, then planes out. This triggers the CHECK ENGINE light. The vehicle runs fine after that, but the light stays on. The first time, the dealer reset the light during a visit for a brake rotor issue, but found no problems. Gas cap OK, both times. Suggestions?
tw
What code?
I haven't had the error checked this time for a code, but the problem is exactly like last time. I'm pretty sure the code was P0300 last time.
tw _____________________________________________________________________
2003 TJ Rubicon * 2001 XJ Sport * 1971 Bill Stroppe Baja Bronco"There is a very fine line between 'hobby' and 'mental illness'."
Pronunciation: 'jEp Function: noun Date: 1940
Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase') A small general-purpose motor vehicle with 80" wheelbase, 1/4-ton capacity and four-wheel drive used by the U.S. army in World War II. _____________________________________________________________________
Billy Ray wrote:
Well.... it would be best to know what the code is this time even though the symptons are similar.
Yes, it would. I don't have a reader, so I'm looking to try a few common things prior to paying for a service visit.
tw _____________________________________________________________________
2003 TJ Rubicon * 2001 XJ Sport * 1971 Bill Stroppe Baja Bronco"There is a very fine line between 'hobby' and 'mental illness'."
Pronunciation: 'jEp Function: noun Date: 1940
Etymology: from g. p. (G= 'Government' P= '80 > Well.... it would be best to know what the code is this time even though the
May I venture a guess? I've seen this before and the cause is pretty obscure, even to seasoned mechanics.
I am assuming you have the 4.0 with hydraulic lifters.
Sometimes, rarely, a stuck oil pressure relief valve piston will cause the valves to hang upon when the engine is started cold, creating a loss of compression, which triggers the MIL. Usually, the valve will settle back into its normal position and all symptoms dissappear. Sometimes for a long time, sometimes for a day.
Usually, you will get a bunch of codes aside from 300 pointing to individual cylinders that are misfiring along with the 300, sometimes not, depending on how the PCM was programmed.
If this is only happening when the engine is cold, this would be my best guess. You could hook up a known-good oil pressure guage to verify this. Other symtoms of this include oil filter expansion, oil leakage, stalling on initial startup and hard restarting.
You will have to consult with your mechanic about a remedy; I can't help you there.
-JD
I should also mention that high RPM valve float will sometimes cause this as well, just in case someone here gets a P0-300 after drag racing a Honda Civic. :)
-JD
The procedure is outlined here or if you stop by almost any auto-parts store they will lend you a lend you a reader at no charge or they may read it for you if they are not busy.
Suggestions?
Or maybe the idle control circuit just wasn't able to respond as quickly as it should to the unusual needs of a cold engine, hence the stumbling and check engine light. When one of my vehicles acts a little "cold blooded" in the morning, I just feed it some throttle. That usually fixes things. I have triggered the engine light trying to crawl up a trail, at an engine speed that was really too low, and almost stalling the engine. I don't know if I would even bother trying to track this down, if it has only happened twice in 50k miles.
Earle
You aren't one of those people who covers the 'check engine' light with a piece of black tape, are you?
My Actron OBD scanner paid for itself the first time I used it. Just used it to run a pre-emissions inspection check, and it caught a small item that would have failed me. C'mon now...be a big boy...go buy one. If it makes you feel any better, you can use it on any late-model vehicle. Your neighbors might even want to slip you a 20 to borrow it now and then.
I would, but I haven't found one that would do my TJ, XJ, Titan, and Aerostar.
tw _____________________________________________________________________
2003 TJ Rubicon * 2001 XJ Sport * 1971 Bill Stroppe Baja Bronco"There is a very fine line between 'hobby' and 'mental illness'."
Pronunciation: 'jEp Function: noun Date: 1940
Etymology: from g. p. (G= 'Government' P= '80 inch wheelbase') A small general-purpose motor vehicle with 80" wheelbase, 1/4-ton capacity and four-wheel drive used by the U.S. army in World War II. _____________________________________________________________________
JD Adams wrote:
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