Codes P0325, P0420 and P0744 fluctuating RPM's

ASHJENREE1

MEMBER
1998 NISSAN ALTIMA
2.4L
4 CYL
FWD
AUTOMATIC
240,000 MILES

Last week had no fluid so I added some did a Lucas treatment put gas treatment and power steering fluid. Codes are P0325, P0420 and P0744. When car reaches ten to fifteen mph it goes into first, then hits twenty mph and the rpm's go to 4000-5000 if I push accelerator I can force it. It gets up to forty five but as long as the pedal is pressed the rpm;s stay high. The engine is loud if I release pedal the rpm's go to 1000 until pedal is pushed again. When in reverse steering wheel is shaking and hard to turn and car squeals loud. Somebody please help me!

1 Reply

STEVE W.

MECHANIC
12,963 POSTS

P0325 - Knock Sensor Circuit Malfunction - Could be a broken wire or bad sensor. Scan would let you see the sensor as you tapped on the block as a test. You could check the wire to see if it is broken but that' I about all without the test equipment.

P0420 - Catalyst System Efficiency Below Threshold (Bank 1) - Could be a bad O2 sensor or more likely the converter is starting to fail from age. Scan tool would let you run a test to see how the sensor is responding.

P0744 - Torque Converter Clutch Circuit Intermittent - The last one and your symptoms basically say the transmission ran low of fluid, got hot inside and burned the clutches and warped the steel plates. Also know as - time to rebuild the transmission.

The loud squeal and hard to turn suggest that the power steering pump is failing as well.