New Boxster/Porsche Owner Need Help Please
 

Hello All,
I recently purchased a 1999 Porsche Boxster with 83K miles on it. It ran fine at first and seems to run fine intermittently. The car now has a pretty extreme hesitation and stall that will usually start after WOT. I just had it completely checked out by an experienced Porsche mechanic but of course it was behaving fine that day. It is not sending any engine codes. He smoke tested the engine and looked for any stored codes but found nothing. At first we assumed that maybe I had just gotten some old gas as not many stations are moving the high octane these days. I replaced the spark plugs today and changed the oil. The ignition coils appear to be in great shape and are not the original but Beru brand. To me the issue feels like some severe misfiring or fuel supply issue. Any ideas on things I should check next that would not throw a code?

Welcome to the board.

Fuel pressure?

Fuel pump relay?

Fuel pump?

look at Brian Minson's U tube channel he just dealt with that...maybe yours is a filter.?

Thank you guys! I went on a 20-30 mile drive yesterday and ran it to about 110 mph. I finally got a CEL and received P1128 and P1130. They of course disappeared again today and the car is running perfectly yet again. It seems to be an every other day type of malfunction at this point. I'm going to try to replace the MAF sensor and see if that clears it up. If not, next maybe the fuel pressure regulator. I'll post an update as to what resolves the issue, assuming I get it resolved, so that others struggling with the same issues can save some time, parts, frustration, etc.

Thank you guys! I drove it about 30 miles yesterday and ran it to about 110 mph. Finally got a CEL with codes P1128 and P1130. Of course the CEL is off today and it is running perfectly. It seems to be an every other day malfunction at this point. I'm going to order a new MAF sensor from Pelican's and see if that does in fact resolve the issue. If not, maybe the fuel pressure regulator? In any case, I will post the solution here for other members that may encounter the same issue.

A vacuum leak is a likely suspect. Try inspecting vacuum lines and maybe spraying some starter fluid around connections in the intake system with the motor running. If you hear an increase in rpm, you’ve found your leak. Try the easy stuff before throwing parts at it!

Could be fuel pump,or filter, pull some of those new spark plugs to see how they are burning. That's the easy way to see what's going on inside. I bet the trouble code was from running lean