Hello all. 2008 GT with a cold-air intake and long tube headers.... everything else stock. I've done some searching around the threads, but haven't found any talking about my particular issue. I was driving on the highway on a two hour trip, and about an hour into it, I slowly cruised up to around 87 or so to get around some traffic (I'm pointing this out because I didn't "gun" it, I just gradually increased my speed). I noticed a slight loss of power and a chugging sound as if my exhaust was being muffled. I quickly got into the right-hand lane and took the next exit less than a mile down the road. As I took the exit, my chugging got worse, and then stalled out as I entered the first gas station close to the exit. Someone helped me push it into a parking spot, then I tried to calm down and figure out what had happened. I checked my oil level and there was no reading on the dipstick. I went in and got two quarts of oil and added them and it brought the level back up to within a quart of full. Then I waited probably another 15 minutes to let things cool off and I cranked it up again. It again started chugging pretty heavily, but didn't stall out again. I was able to limp it the rest of the way to my house, and it seemed nearly normal at around 55 mph, but with noticeable reduction in performance if I tried to accelerate. -- It's been a few weeks and I have replaced the lash adjusters (lifters), VVT solenoids, and cam phasers (the camshaft itself doesn't have noticeable wear on any lobe... it all seems pretty normal), but the problem persists. As soon as I start the engine, it is a rough idle. If I rev it, it is a hesitant rev as if missing something. When I was driving it, it backfired a lot. -- On the passenger side of the intake, it appears that oil has been seeping through above the sparkplugs holes (not coming from the sparkplugs, but above the cylinders as if coming from the intake)... this is new, I don't think this existed before. It's as if someone dripped some motor oil onto the passenger side of the air intake, right above the spark-plug cylinders. It is seeping all around the fuel injectors (but it doesn't smell like fuel). I'm thinking I might have some sort of a PCV issue. A friend suggested that my timing may be off because the tensioners may have lost pressure due to low oil. I'm not so sure, since the intake has this oil seepage thing going on. Thank you for any and all help

 

If you have a cold-air intake and LTs, then you should have an aftermarket tune, correct? And hopefully a handheld programmer (SCT, Diablo, etc).
Is the Check Engine light on? If so, can you use the programmer to read and share the trouble codes with us?

My first thought was actually a fuel pump issue (there was a TSB where the car would hesitate/buck, usually during high speed acceleration), but...given your other symptoms I doubt this is the case.
My second thought was a cylinder misfire; maybe a spark plug or coil has given up. Given the location of your oil seepage issues, maybe enough oil has saturated a coil and it's given up. I am pretty sure a chronic misfire would throw a trouble code. IMO running rough + backfiring means it's not firing all cylinders all the time and there's un-burned fuel.

Obviously low/leaking oil is not great; it may or may not be related to the rough-running issue. I don't have any ideas on this front, except that your "PCV issue" theory seems plausible.

Trouble codes, if available, would probably shed some light.

 

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Thank you for the reply
Unfortunately, I do not have the hand-held tuner. I bought the car a few years ago after a friend of mine in the Navy passed away, leaving his daughter with his estate. I bought it from her, and she kept the tuner for some reason (I think she thought it was some kind of multi-meter). I didn't know exactly what it was at the time, either. There are no codes and no check-engine light. Would purchasing another tuner at this point be helpful? Thanks again.

 

Is there one that you would recommend?

 

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Thank you. Is there a datalogger that you would recommend? I see a really wide range of options when I look at them.

 

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Hello again,

I was not getting any codes, but these just popped up:
P0345 Camshaft Position Sensor 'A' Circuit Bank 2
P0349 Camshaft Position Sensor 'A' Circuit Intermittent Bank 2

I replaced the sensor, but the code continues to be discovered by my scan tool, although it doesn't light the CEL.

I think this may indicate out of timing.

Thank you.

 

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