You must check fuel pressure with the engine under load, i.e. running down the road.
That can cause all sorts of weird problems. They will need to be replaced.
That is an electrolytic capacitor or what is commonly called, a cap. They have a definite life cycle and after 22 or more years, they start to fail. The failure mode is they dry out because the liquid electrolyte leaks out. Then they burn up or blow the top out of the can that they are packaged in. A clue to failure is the top of the can starts to bulge. When you see one bulging it has either failed or is in the process of Many of the automotive computer repair places will replace all of them as a first step in any repair efforts. The capacitors have a voltage rating, a capacitance rating, a tolerance for the capacitance rating, an operating temp rating and a life cycle rating. They also have a specification for cab size and lead placement
The higher the voltage rating, the larger physical size of the capacitor when compared to one with the same capacitance and a lower voltage rating. Most of the ones used in automotive electronics have a 20-35 volt rating since they are used in low voltage circuits. Using one with a higher voltage rating doesn't hurt anything, but it usually doesn't have any benefits either. There may be a size limitation because of the way the circuit board is laid out. That means there are sometimes limits on replacing the 20 volt cap with a 35 volt cap because it won't physically fit in the space allocated on the circuit board.
The higher temp rating and longer lifecycle ratings increase the cost of a capacitor. In automotive circuits, those are important factors, and the highest rating stands the best chance of lasting the longest and working the best. Most capacitors used in automotive applications are rated at 105° C The typical capacitor used in most automotive electronics is less than $1.50 each.
Some informative help from YouTube…
WWW.digikey.com or www.newark.com are good sources for capacitors, resistors and just about any other quality electronic part. Avoid Radio Shack unless it is a temporary repair or emergency situation. Almost all of their parts are less than top quality stuff and a lot of it is just plain junk.
That's the easy part now here comes the gotcha... The circuit boards are almost all multilayer construction. That means you have to be able to apply enough heat with a pencil tip soldering tool to melt the solder on at least 4 layers and some times more. Then you need to have a solder sucker to suck up the solder once it turns molten but before it burn or damages the PCB (Printed Circuit Board). I have been fixing PCB's in computers for40 years now and it is still a challenge to do it right and not make a mess of it.
The capacitors have a stripe on the side of the can that indicates polarity. Make sure that you match the polarity markings on the capacitor with the polarity markings on the PCB.
Some more help from YouTube…