night7519

This is going to be a long post but I feel I need to give some back story to describe the problem. Please excuse the lengthy post.

I have a 2005 GT with hot rod cams, Roush CAI (Airaid), and the FRPP intake manifold.

Shortly after installing the FRPP intake and cams last April I started getting the p0174 and p0171 error codes. I also had a bit of oil showing up in the valley between the heads and the intake manifold. It seemed to be dripping off the bottom of the bolts connecting the top and bottom sections of the intake manifold. I was able to identify a couple of bolts on the drivers side that had "more'' oil on them so I took them out, put some RTV in the bolt holes and tightened the bolts back down. Viola! No more codes. I have on rare occasion seen a bit of oil in that same valley on the passenger side but it is very rare.

Fast forward to the end of last year when the weather started getting cold. I had driven the car to work one day and when i got in it to leave for home that afternoon I started the car like normal with my foot OFF the accelerator. The car started and the RPMs jumped up to around 1500 and started to drop back down to idle. Just before it settled back to normal idle it surged again this time running up to little over 2000 RPMs where it stayed for a couple of seconds and then started dropping back down. To my surprise, instead of dropping back down to idle it stalled. I had a hard time getting the car restarted but was able to do so after a couple of attempts and giving it some gas. Car ran fine all the way home and once home I turned the car off and restarted it with no issue.

The next morning it did the same thing; started fine, ran up to 1500, started to drop back to idle, surged to 2000 and stalled. I was able to get it restarted by again, giving it a bit of gas. This behavior occurred a couple more times of the next few days and then went away.

Shortly after the problem seemed to go away, I got a P0300 code. I cleared the code and no real problems afterwards.

Over the next several weeks, this behavior has reappeared a few times. I might go 3 or 4 weeks with no issue and then out of the blue it would surge and stall on cold start up. It would happen a couple of times and then clear up. Up until a couple of days ago, this hadn't happened for a least a couple of months and I hadn't seen the P0300 code again since that one time.

Fast forward to last weekend. I went the drag strip for the first time and made 4 passes down the 1/8 mile. On my way home I noticed the check engine light was on. When I got home I pulled the codes and had a P0171(system too lean bank 1) and P0300 (random misfire). I cleared the codes and the car seemed to be running fine. I checked for oil in the valley between the head and intake (since that's where I had seen it before when I got the P0171 code) and found nothing. Car ran fine for the next couple of days then on Wednesday of this week, I had the same cold start up issue again. This happened Wednesday afternoon and again Thursday afternoon.

Car started and ran fine this morning. Car has actually run fine through all of the above tale of trouble codes.

Any ideas what might be causing the cold startup surge and stall and/or the trouble codes I mentioned?

I must also mention that I am still running the plugs that came on the car and they now have about 77K miles on them so that is my first guess as to the problem. I know I need to get the plugs changed soon but wanted to see if any of you folks might recommend anything else that may be causing any of the above issues. Thanks much for reading through all this!