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I have a 03 Jag Stype with 153k on it. I’ve no problems with the vehicle at all up until recently. Was running bad and kicked out some codes. Had misfires on 1, 3 and 5. I had never changed the spark plugs so I knew that was something that needed to be done. So I changed out-
Spark plugs
Ignition coils
Upper intake gasket
left and right valve cover gasket as well as spark plug well gasket.Doing all of that stopped the misfires but the car still isn’t running well. It’s quite a bit louder and when I floor it the engine struggles and pretty much cuts out when it gets to around 3k rpm. Once I settle in to my cruising speed, whether it be 30 or 60 or whatever the engine runs perfectly. I’ve run some live data on it and here’s one of the problems but I don’t know what’s causing it and what else to look at.
My ltft numbers at idle and 2500 are
1.8 and 16.8 at idle (1st number is bank 1 and second is bank 2)
-.8 and 14.8 at 2500 (same as above)
Also when I’m driving under load and gas it the bank 2 ltft never gets above 19.5, as a matter of fact it pretty much just stays there unless I let off the gas.
I’m lost on what to do or look at next. I think because the two numbers are so different it means I don’t have a vacuum leak, is that correct?
Thank you very much in advance for any helpful knowledge you can send my way.
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with the car sounding louder and the positive fuel trim
Check for exhaust leaks before the o2 sensor.http://www.ericthecarguy.com/faq/solving-automotive-performance-issues
One more question. If I can’t find the exhaust leak could I just unplug the o2 sensor on bank 2? If the vehicle kicks to a basic reading when it’s unplugged then that would bypass it reading the change from a leak. Hopefully I’m making sense.
Forget my last post, read more and sounds like a bad idea.
Would an exhaust leak before the first 02 sensor cause it to have off readings on my odb tool?
[quote=”WoodyBing” post=107987]Forget my last post, read more and sounds like a bad idea.
Would an exhaust leak before the first 02 sensor cause it to have off readings on my odb tool?[/quote]
The exhaust leak acts as a vacuum leak which fools the o2 back to the
ecm to think its running lean and wants to add fuel. a little seam
to get a little smoke will aid in the leak finding with the rag on the
exhaust outlet.I know you say you’ve done the upper intake gasket, but I would still check for vacuum leaks for good measure. As College man pointed out, exhaust leaks before the O2 can cause this type of issue, but it’s actually more common that a vacuum leak would cause an issue like that. As pointed out in the article that college man posted, you also want to make sure the engine is mechanically sound. Perhaps do a compression test and check the mechanical timing. A mechanical issue can often cause a performance problem but it is so often overlooked.
Good luck and keep us posted.
Eric, am I wrong in thinking that if there was a vacuum leak in the intake that it would effect both bank 1 and 2. I’m just getting bad fuel readings from bank 2.
Went back thru my work today, took off intake manifold and made sure my plugs looked good and all bolts tightened down to specs. Car still driving like crap. Sounds good at idle but when I got to drive it sounds horrible and cuts out at around 3k rpm. My codes are-
P1300
P1316
P0300
p0301
p0303
p0305there is also one for my coolant temp. I used a temp sensor from Autozone so I think that might be giving me a bad code on it. Temp on coolant is ok when the car is warm.
So, I’m back to misfires on the same side that I had misfires on before I changed everything out. Strange to me that this would all be on bank 1 but my LTFT2 is the one out of whack.
I also checked for leaks in the exhaust but I didn’t see or hear anything.
I haven’t done this with this car or my Rover in years but I may break down and take it in this week. I need this car to be working. Any ideas before I take it in? I’ve looked for vacuum leaks but have had no luck finding one.
I was thinking because I had misfires for too long that I might have burnt my passenger side Cat up. So I decided to unplug the 02 sensor on that side. Not a ton better but the vehicle isn’t cutting out at 3k rpm like it was before.
Took the Jab into a place and they did a smoke test for an exhaust leak but found nothing. They looked it over but couldn’t figure it out. It’s a German European mechanic at that. I think he just doesn’t want to dig too deep. I’m not sure what to do at this point. The car in good running condition is only worth 3500. It’s at an age where I’m not sure it’s worth spending too much on someone else to fix it. I may see if I can find someone that can do a back pressure test to see if my Cat is fried.
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