KA24DE running bad

[InitialDGuy]

Ok,

A few days ago my engine began idling erractically, and then it proceeded to begin to hesitate a short time after that. Well, yesterday I went to start the car in the morning, and it was running like crap! I mean it heasitates badly under any kind of acceleration, and backfires alot under decelleration. It also sucked down a little over 1/4 of a tank of gas in about 30 miles. I put new plugs and wires on the car last week. I checked to make sure that I didn't have any plugwires crossed, all four cylinders are getting spark. I checked the injectors by first unplugging them one at a time as the car was running to see if there was a noticable change in idle, and each time the idle changed the same, more or less. I also check the resistance on each injector, and each one came out to 11.5 ohms +- .10 ohms. The compression on each cylinder was also well within spec. I pulled the ecu codes and "Code 55" came up, which is of course all clear. At this point I am really stumped as to what the problem could be. I did add some fuel system treatment yesterday and in all honesty, that just made the problem worse. Any help or suggestions would be greatly appreciated.

[wiwalsh]

Timing?? MAFS loose connection or bad??? Supprised you havent thrown a code if its acting as bad as you say it is.... How about fuel pressure and fuel filter? Air leak in the intake duct? IAA valve?? if you have an FSM run the tests for these....

[quiksilvia]

whate grade of gas?

[red240ne]

don't forget about your 02 sensor, because all of those symptoms can be related to a faulty 02 sensor. check your 02 connections and pull the sensor out and lightly shake it. if it sounds like a broken light bulb, then the ceramic stuff inside is broken and it's not functioning properly.

whenever i get back in town we can try the 02 sensor thing. i have a brand new one lying around.

[InitialDGuy]

I forgot to ad that I recently installed both a new o2 Sensor and a new Nissan fuel filter. I am going to test the MAF and a few other misc things tomorrow morning and see where that gets me. Luckily I have an entire spare motor laying around, as well as its related electrical componentry.

[Queamore]

Check for any cracked air/fuel lines if it's sucking in air or leaking somewhere it might not throw a code but still drive like crap.

[NISTECH]

check your coolant temp sensor

[InitialDGuy]

Well,

I found and fixed the problem. At first I tested the Coolant Temo Sensor as advised, and found it to be defective. 'Ok' I thought, 'This must be the problem!". Well, I pulled a sensor out of a parts motor I had laying around and installed it. No difference. The car still ran horrible. I even waited until the car had warmed up to the proper levels and tested the replacement sensor to be sure that it actually was working. It tested dead on spec. So, I started poking around the fuel rail and noticed that the No. 4 Injector was leaking. So I spent an hour pulling the fuel rail off and after I pulled the rail, I spotted the problem straight away. The cap on the bottom of the 4th injector was simply NOT there. I mean it was gone, completely. The injector also looked all burnt inside, as opposed to the other 3 injectors, which all looked fine. All of the seals were also all cracked and dried out. I swapped in a different fuel rail w/ 4 nearly new injectors on it, and the car ran like a champ afterwards. I still need to change the oil as I am sure there is some gas in there from the faulty injector dumping fuel in like crazy. I am also going to remove the AIV assembly as the idle is a tad erratic at times and the acceleration is still a little rough right about 3 grand for a few moments. Still, all things considered, I am happy that this turned out to be relatively easy to fix, and that it wasn't a burnt valve or something equally ****ty.

Thanks for your help everyone.

Adam