Hi! Car suddenly started idling rough (low RPM, engine struggling) when I started it and threw P0087. Noticed trunk wasn't opening with key fob and just weird electrical things going on with the car so tried resetting electrically and was able to drive home fine.

A few hours later, tested idle again and it's running smoothly at 44-47 PSI at idle. Could it just be an electrical gremlin or should I try to replace the fuel pressure sensor? Thanks!

 

Also noticed this plastic line broken around the fuel pressure sensor. Could that be contributing to the problem?

 

Hose connects to the supercharger and bypass valve, I doubt it would affect the fuel pressure.

How old is the battery - aging batteries can cause weird problems.

 

Battery is 4 years old!

 

I can't actually see where the line is broken but if it is the vacuum line itself that is broken, rather than an attachment clip, then the fuel pressure sensor/regulator cannot take account of the intake vacuum and the fuel pressure will presumably be incorrect. I would definitely fix/replace that line before proceeding. You could do it for testing purposes by cutting in and bridging the gap with a short length of suitable plastic tubing, or even just taping it as a short-term bodge.

Definitely make sure the battery is fully charged as well.

Richard

 

You may need a new fuel filter.

 

P0087 has no extended codes listed:





An error code is recorded for two reasons:
1. actual fault
2. out-of-range signal

The only code related fault here that could be transient and fix itself is restricted fuel. A circuit or sensor fault or a failed fuel pump won't go away without intervention and repair. If you clear the code and it comes back, you have a harness or component issue. If it doesn't come back, it was very likely just an out-of-range signal.

A four year old battery and other weird electrical phenomena occuring. I know where I'd put my money.

Graham

 

I've already put my money on the broken vacuum line to the sensor, assuming that it is broken in a way that is affecting the intake vacuum as seen by the sensor.

 

Regardless of the current DTC, a new and fully charged battery would be a wise investment. Make it an early Christmas present to yourself.

 

I just changed my battery due to erroneous faults twice in a week. No problems since the new battery.

 

Certainly would. This is a vacuum hose from the side of the TB to several other locations. Different places on the NA and SC, and I assume on the 4.2 and 5.0, but one is the fuel pressure sensor. Breaks incredibly easily after 10 years in the heat on top of the engine.. Causes severe vacuum leak, and many of the symptoms you had. If any X150 starts running rough, check this along with the top few usual suspects, such as coil and open breather hose, etc. Good news is that it can be quickly fixed with the right size ID rubber vacuum hose from a parts shop. Just make sure there's still a half inch of tubing available near the connectors to push on the new vacuum hose.

Below is a pic of the sensor. The tube connector sticking out has one of the above vacuum lines attached to it. As I understand it, the FPS has to compensate for engine vacuum to establish correct pressure.

 

Post #5 presumably fell on stony ground. 😉

 

Thanks guys - the vacuum hose was broken in multiple places so hopefully that's the culprit. New part should be here this week!