Hi all...second post here. First is in newbie thread. I recently (2 weeks ago) purchased an 04 XJ8 with 60k miles. Great car and love it! Quite a change from the Wrangler Rubicon I traded!!

It has done a couple of odd things and I want to get an opinion on if some of you may think they are related. First, occassionaly on start up, it will hestitate to idle for 30-60 seconds and run roughly but eventually smooth out and then be fine the entire time I am driving. Only runs rough on start up and only on occassion. Second, my wife started up the car the other day and it gave the initial RPM run-up and then died. It did this twice in the driveway, but when I went out and started it, it fired right up with no issues. It has not died since. Third, one time upon start-up I fired it up and immediately put it in drive which caused it to run very rough and throw a check engine light. The code gave me a 1-3-5 missfire which I attributed to my haste in throwing the car in gear. It hasn't done this since clearing the codes 4 days and 300+ miles ago. Last, last night, it threw an air suspension fault for a brief period and then it went off without a restart. This morning, I drove approxiately 5 minutes to the gas station with no errors. Filled with gas, restarted and drove off. Approximately 5 minutes later, I got the fault again and it stayed on the duration of the drive to the office. I haven't restarted since.

My question is, would the battery going down give me all these weird anomolies or do I have a bunch of components failing at the same time that are completely unrelated??

Thank you for your assistance and apologies for the novel!

 

Battery is not a bad thought at all. All these systems need a constant power source or weird things begin. Makes sense.

 

VAT Battery tester says battery is good but it's at 60% capacity and at 12.4V instead of 12.6V. Is this enough to start tripping codes or do I have a compressor issue?

 

You may want to get the injectors cleaned. I had it done once at 45k on my 04 XJ and it helped with both idle and smoother acceleration. Cost about $200.

The air suspension fault is pretty common in the 04 models; the cause can vary widely. There are several threads that discuss that issue at length. Do a search and you will get a ton of info.

 

this time off year is a comon issue with cold start performance with varying temps and fuel blends. The car doesnt read 02 sensors till they heat up and comeonline (which is why they have internal heaters now to speed it up) until then the ecu goes on a cold start perfomrance map and it runs richer too when cold to speed 02/catalytic convertor lightoff. This leads to a rough idle at times during cold starts. cleaning the injectors is a good option cause any dirty poor spray patterned injectors will make this more pronounced. Just dont think that what you put in your tank will do anything

 

I'm only seeing the fault every other time I start the car and even then maybe not that often. Could it be temperature related and should I just worry about it if I see it every time I drive the car? It is annoying, but if it isn't that big a deal, I'll just put it off for now.

Advice?

 

My 05' VDP got its first check engine light today at 71,000 miles. I got the same 1-3-5 misfire code. I'm going to Change the fuel filter and plugs but I'm pretty much stabbing in the dark.I figure I need to change these anyway. Let us know if you figure it out.

 

Is the fault the check engine light or the suspension fault? I get a suspension light when the outside temp gets below 35 degrees. Most people on this forum believe the air pumps start to go when that happens. I plan on driving it until it fails and get all I can out of the old one. The check engine light for misfires on 1-3-5 sounds a little weird. Most cars alternate the cylinder desination so all odds are on one side and evens on the other. What are the odds of 3 cylinders misfiring in a row? I havn't looked, but they may use the same wire harness for the coils. Plugs are cheap and easy to do. I almost always replace them on new used cars. Bad plugs can cause all types of problems from destroying coil packs, O2 sensors and converters.

 

Just a suggestion on the air suspension fault. If you are in fact pulling a C2302/3 code, after you replace the air compressor, it pays to check all of the air terminals with a soapy water solution. I just replaced an air compressor on an 04 last week and found a slow leak on the RF shock terminal. Although the compressors go fairly frequently, the failures are exacerbated by leaks that cause them to run far more cycles than they should.

Also, I wouldn't personally push the compressor failure as far as I could. Once you start getting the suspension fault light on frequently, like every drive, its better to change it as it is taxing the entire system trying to keep up with the suspension demand. Additionally, when you change the compressor, strongly advise you replace the R1 relay in the engine compartment, especially if you do push the bad compressor for awhile before changing.