Z4Ccoupe

I just purchased a 30th Anniversary T/A. The car has been parked for over 2 years. It was running horribly when I first got it. The owner told me she had replace the TPS, trying to fix it. The SES was on but the only code showing was the secondary air code. I researched here and found it had a blown air pump fuse. Easy fix. But that didn't fix the poor running. I have no idea what grade of fuel was in it. I suspect regular. I put in 8 gal of Premium. Drove it a little and got P0171 and P0332 codes. The car would run poorly when cold and OK when hot. I finally went for a 50 mile highway run. It ran great when I got through. And it only showed P0332 code during that drive. This morning, it still ran a little sluggishly when cold and I had some exhaust pops during shifts. It seemed to run OK when hot. But it was a short drive. Should I just continue to run more good gas through it, or do I have a real problem?

Injuneer

P0171 was telling you the driver side of the engine was running lean. Most likely gummed up injector(s) from sitting for 2 years. May have cleaned up a little from the drive, but still running lean, contributing to the problem. Try some fuel injector cleaner added to the fuel. If that doesn't eventually smooth it out, professional injector cleaning may be required. Probably also a good idea to check the fuel pressure, both at idle, and with the engine under load. You want to make sure the filter is not dirty, and the sock on the fuel pump suction is not plugged up.

P0332 is telling you one of the two knock sensor circuits is faulty. Typically when the code sets, the PCM retards the timing to protect the engine. That could contribute to a sluggish feel. Right now I can't access my digital copy of the 99 factory manual, to review how to check the circuit. This can be a PITA repair, because the two knock sensors are under the intake manifold.

Z4Ccoupe

Into my second tank of gas. I put in a K&N filter and cleaned the MAF. It looked dirty, from what I can tell. Went for a 35 mile run with some highway and some city. The car is running much better and the good thing is that I didn't have any codes. That's a first.