2001 cherokee sport -- engine light / flashing *HELP**

[markoxj]

So it was an off and on situation in which my engine light has been off and on.. running rougher from when I first got it.. So I read up online and read that the issue could be the:


spark plugs
fuel injectors
spark plug wire..etc.

I then went and replaced my spark plugs (old ones weren't too bad, but it was probably time to replace them anyway)

I replaced them - leaving the existing coil boots cause they weren't in dry rotted or in bad condition at all..

So I headed back to napa to return some extra parts and now my engine light started to flash... When i arrived I asked to borrow the computer and plugged it in and got two codes --- P0303 and p0306, which just so happen to be misfire in cylinder's 3 and 6.
Issues leading to this problem could be a number of things.. sparkplugs-fuel injectors-spark plug connections..you get the point.

I then went on and tested the ohms of each fuel injector points -average is about 12 ohms (or so i read)- Tested each and this is what I got.

Cylinder Ohms reading
6 11.1
5 11.2
4 11.1
3 11.5
2 11.6
1 11.3

So the range was relatively close, nothing to far out of range that would state that there was a poor performing fuel injector--right?

So now im in a pickle.. and money of course is tight.. What else should i do/test? Is gapping the spark plugs a big deal and could have effected the performance afterwords- is it too late to go back and fix the ones I just bought?


I've also heard that "heat soak" is common in 2000+ jeep cherokees.. With vaporization effecting fuel injector #3... I don't like to think this is the problem cause its been 20-30 degrees not 90+..

Anything will help!! Thanks

[Mudderoy]

So it was an off and on situation in which my engine light has been off and on.. running rougher from when I first got it.. So I read up online and read that the issue could be the:


spark plugs
fuel injectors
spark plug wire..etc.

I then went and replaced my spark plugs (old ones weren't too bad, but it was probably time to replace them anyway)

I replaced them - leaving the existing coil boots cause they weren't in dry rotted or in bad condition at all..

So I headed back to napa to return some extra parts and now my engine light started to flash... When i arrived I asked to borrow the computer and plugged it in and got two codes --- P0303 and p0306, which just so happen to be misfire in cylinder's 3 and 6.
Issues leading to this problem could be a number of things.. sparkplugs-fuel injectors-spark plug connections..you get the point.

I then went on and tested the ohms of each fuel injector points -average is about 12 ohms (or so i read)- Tested each and this is what I got.

Cylinder Ohms reading
6 11.1
5 11.2
4 11.1
3 11.5
2 11.6
1 11.3

So the range was relatively close, nothing to far out of range that would state that there was a poor performing fuel injector--right?

So now im in a pickle.. and money of course is tight.. What else should i do/test? Is gapping the spark plugs a big deal and could have effected the performance afterwords- is it too late to go back and fix the ones I just bought?


I've also heard that "heat soak" is common in 2000+ jeep cherokees.. With vaporization effecting fuel injector #3... I don't like to think this is the problem cause its been 20-30 degrees not 90+..

Anything will help!! Thanks

What is the CEL code?

This reminds me of when my 1998 was doing this. It was a misfire. The flashing was bad. If memory serves, it was a wire rubbing from the cable bundle on the fuel rail. I pulled the bundle up and off of the fuel rail with some nylon tie wraps.

[markoxj]

No cell codes come up... I tried doing the 3 click trick turning the vehicle on but not turning the engine over.. nada

[gary63]

the 2000 and 2001 have a different exaust header if you run the motor so it reaches running temp. and shut it off then restart it alittel after the fuel in #3 and #6 will sometime evaperat and will cos a missfire.it will trip the check eng. light but most of the time if will smooth out and run ok.Jeep & dodge had a flier the said to cover the 3 & 6 with insalaters you can get from them for $$$$ or go to the parts store and pick up some. there is alot of types.

[nickxj94]

Sounds like heat soak to me my 2000 does it in 20* weather too it don't matter it's when it reaches running temp about 220* and you park it and shut it off for less than 10 mins it will run rough everytime. I usually try to leave it running if I'm running in the store for a few things or just stay longer I let mine sit for least 20-30 minutes when possible it don't ever run rough since I started doing that.

[gary63]

I have been tring spark plug wire insulated boots.I took the injecters off slip them through the boots and re-install so far no more problems.

[markoxj]

UPDATE--

So I've gapped the spark-plugs correctly, changed the coil boots on 3 & 6, (because of misfires, last resort before new coil rail?), still have a light and it comes on even when i disconnect the battery/ erased with a comp system...

So, do YOU think it's the coil rail? My mechanic friend said it sounds like that, but online i'm hearing so many different things...

[markoxj]

UPDATE 2:

Sorry to spam if this thread keeps getting bumped....

Problem fixed! Ended up replacing the whole coil rail, erased misfire codes and then turned on the jeep again. No engine light! runs way smoother. It was a shot in the dark, as it could have been multiple things...but I guess I lucked out this time!

Hope this helps others!