I recently bought a 1998 Accord LX 2.3 Vtec AT. Looks good ran very well when I did a test drive. Soon after it started to run rough at idle. I put a can of Seafoam in an empty tank and filled the tank. Within about 20 miles the CEL came on and it was running really rough at all engine speeds. The CEL started blinking so I stopped and turned it off. I was 15 miles from home. I started it again and the CEL was on but not blinking so I drove it home. The next day everything seemed to be OK. Mysteries abound. Two days later I had to deliver another car 180 miles away and my son followed me in the Accord to bring me home. 20 miles into the trip the CEL came on (not blinking) and he began to have problems with low power and very rough engine operation. We had to do the trip and we made it. I changed the spark plugs which seemed to help a little. The car used a lot of gas on the way up, I filled it up to come back. Seemed a little better. The problem persisted though. I ran both Techtron and Gumout cleaners through it. I changed the front O2 sensor. It seemed to help. I took off the EGR but it didn't seem very carboned up. It seemed to help a little. I cleared the codes and the CEL didn't come on for 100 miles or more. It just came on again and the codes are P0170 and P0171. I get about 11 MPG, have rough idle and very poor power. Thoughts?

 

I'm going to lean towards the O2 but we need to test a few things.

Can you test the fuel pressure, many places rent testers?

Do you have a volt meter to do the next few tests?

 

I was going to test the fuel pressure next so it is good to have agreement. I do have a volt meter so which test do you suggest?

 

I downloaded the 2520 page service manual for this car and it is thorough and exhaustive. It indicates that you should remove the fuel pulsation damper from its fitting and attach the fuel pressure gauge to the fitting. I was able to borrow an Actron fuel pressure tester from Auto Zone but it does not have the correct adaptors for this application. The Actron manual suggests that the connection should be made at the fuel filter that is in the engine compartment but I cannot identify a fuel filter in the engine compartment. The service manual indicates that the only fuel filter is in the fuel tank. The computer at Auto Zone shows a fuel filter in the engine compartment. I'm finding this difficult. I'm not a great mechanic but I'm a pretty good reader and the conflicting information has me stumped. Any thoughts?

 

Filter is in the tank, part of the pump. As for the adapter, you'll have to look around for the proper one.