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2002 Nissan Altima 2.5L Engine Fault Codes P0301, P1122, P1564, P1126 - Slow Acceleration and Starting Issues

Model: 2002 nissan altima 2.5 Fault Code: P0301 Posted: 2015-09-05 16:06

My 2002 Nissan Altima 2.5L is displaying multiple OBD2 fault codes: P0301 (cylinder 1 misfire), P1122 (throttle position sensor issue), P1564 (fuel pump control circuit malfunction), and P1126 (exhaust gas temperature sensor problem). The codes appear in that sequence, with P0301, P1122, and P1126 repeating. The car starts but struggles to accelerate—maximum speed is only about 5 miles per hour. I recently replaced the mass air flow sensor, oxygen sensors, camshaft and crankshaft position sensors, catalytic converter, and alternator/alternator mount. The previous alternator mount did not belong to my vehicle, and we replaced it because the original mount broke and the new one didn't fit properly. After reassembling the belt, I noticed a loud squeaking noise due to excessive tension on the pulleys. Before the alternator issue, the car ran smoothly with no problems. After installing the new alternator setup, it suddenly shut off while I was slowing down at a stoplight. I restarted it and managed to get home without any lights coming on. The next time I drove, I reached my destination normally but noticed the vehicle only accelerated to 5 mph and the 'Service Engine Soon' light illuminated. I pulled over and had it towed home. Using an OBD2 scanner, I confirmed the fault codes: P0301, P1122, P1564, and P1126. I'm now unsure where to begin troubleshooting. Has anyone experienced similar issues with this model or these specific codes? Any guidance on diagnosing misfires, throttle sensor faults, or electrical system problems would be greatly appreciated.

Related fault codes
P0301P1122P1126P1564
Comments (3)
Anonymous 2015-09-06 16:16

Possible root causes: electronic throttle control malfunction and cylinder 1 misfire. Addressing the cruise control system may help resolve the electronic throttle issue — though this is not guaranteed.

Anonymous 2015-09-20 17:53

I replaced the throttle body and performed an idle relearn procedure, which initially improved performance. However, after some time, the vehicle began losing power again and now only accelerates to about 5 mph. Should I prioritize checking the cruise control system first, or start with diagnosing the misfire? I did replace the coil boots, but my spark plugs appear in good condition — could a faulty ignition coil be the real issue?

Anonymous 2015-09-20 17:54

After replacing the throttle body and clearing the codes, P0301, P1122, and P1126 reappeared. The cruise control has not returned since — suggesting it may not be the primary issue.