My 95 GXE, w/AT & 99K miles just started running rough and loss of power when accelerating. From the posts that I have read, think it may be an injector or fuel related. CEL is not on. Need help with diagnosis of this problem. Thanks.

Kevin

 

i would check pluge and injectors, also, pull codes from the ecu to see the status of the knock sensor, i would put money on it that it is bad by now, but that would not cause any of these probs

 

I think it may be your plugs or other ignition related components. A similar result happened with my 89 Mazda 626. One of the plug wires came off. It felt like I lost 65% of the power and the idle was really rough and loud. If you remove the little plastic panel to the right of you gas pedal, you'll reveal the ECU. Put your key in the ignition and turn the ACC and then turn "ON." You don't have to Start the engine, just get all the red lights on your instrument cluster on. Go to your ECU and read the directions. I think you take a flat head screwdriver; turn clockwise 1/4 rotate, wait 2 seconds, and then turn back 1/4 rotate counter-clockwise. Look up at the instrument cluster and pay attention to the Check Engine light. It will blink a code to you.

follow this:
http://vbxmaxima.8m.com/ecu.html
there is a decoder link too.

 

a broken knock sensor can cause bad gas mileage and loss of power

 

yes it can, the ECU checks all sensors when the car is first started, if the KS is bad, it will retard all timing which lowers milage and power, but it will not cause rough idle, so, i dont think this is the prob here.

 

Test your MAFS also. I had same symptoms, rough idle and power loss when I tried to accelerate. In my case, the MAFS didn't trigger a CEL either.

 

if it is the mafs, i dont think you can rev to over 2500rpm, it will be difficult to start and idle really rough

 

You are correct in most cases. Mine symptoms were minor at first so I was able to start my car easily but the idle was very eradic. After trying to drive it a few times it became worse to the point where it was stalling. It couldn't hurt to test it.

 

Checked the ECU, 5/5, No Failure recorded/detected. I put some Techron in the tank. Next step is to have a local trusted repair service try to diagnose. Last resort is the dealer.

Kevin

 

Test your MAFS... very likely that it might be off but not throwing a CEL... theres some instructions around here but im on my way out the door... do a search or maybe someone knows where to find them

 

Problem resolved. Had 1 dead injector and 2 that were dying, per the tech. On the way to the repair place the CEL came on. He said it showed a code of a cylinder misfire. It was definately getting worse as I was driving it to have it fixed. Since the dead one was on the back (under intake) and 2 dying on front, he put 3 new on the back and moved 2 that checked OK to the front. His experience is that the other 3 may fail soon, but will be easier & less expensive to replace on the front. Parts were $345 for 3 injectors and $250 for labor (about 4 hrs, @ $64/hr including diagnostic time). Total around $600. He sees many Nissans with injector failures between 75k - 125k miles. This is the first car I have had with 99K miles...had a starter fail this past spring, which I replaced myself. Looking for a replacement, '01 or '02 Maxima. Guess I have been lucky in the past with previous Maxima's '84 and '87, less maintenance costs.... I usually buy 1 or 2 year old, with warranty remaining.

Kevin

 

Good to hear