My car has low acceleration and doesn´t reach highway speeds easily, running with low RPMs, 2500RPM max

LOULOWEES

MEMBER
2002 PONTIAC GRAND AM
140,000 MILES

The check engine light is on from around 1 month ago. I got 2 codes: P0141 OBD-II Trouble Code and
P0507 - Idle Air Control System RPM Higher Than Expected. Sometimes the RPMs boost out of control, this happens mostly when operating with the AC on, which it feels like takes too much power from the engine and therefore doesn´t perform well.
In the last 2 weeks my car has low acceleration and doesn´t reach highway speeds easily, running with low RPMs, 2500RPM max, very hard to reach 3000RPM sometimes to pass, with 4th shift.
I found that part of the problem might be a worn oxigen sensor, and I would like to know please if I could do it myself with common handtools, or for the whole problem is better to take the car to a auto service.
Thanks so much
Lou

2 Replies

KHLOW2008

MECHANIC
41,814 POSTS

P0141 - HO2S heater performance bank 1 sensor 2.
P0507 - Idle Speed High.

Job can be done with common hand tools but where diagnostics are concerned, a scn tool is required.

Possibly the HP@s is faulty but we would not know unless you perform tests to find out.

I would suggest starting with the P0507. The idle control has a problem and it could be a stuck open IAC valve. Try cleaning it first, together with the throttle body and check for vacuum leaks.

If no problems are found and problems persistes, continue with the HO2S diagnostics. You would need a test light or DVOM for basic testings.