1998 Pontiac Sunfire sputtering and motor shaking when in gear


Asked by Sep 14, 2013 at 03:49 PM about the 1998 Pontiac Sunfire

Question type: Maintenance & Repair

I have a 98 Sunfire with a 2.2 liter engine and automatic transmission. For a while it
has been running rough and the engine shakes when I shift it in to gear. It is most
noticeable when idling (in gear) but can also feel the engine missing when on the
highway. It idles perfectly in park and in reverse but runs awful in drive. I plugged it in
to a reader earlier today and got P0300 (Multiple Engine Misfire) and P1621 (PCM
memory performance) so I am thinking the PCM needs replacing... Is this likely to be a
solution or might I have a larger problem where the engine is connecting to the drive
train? Sorry, not an expert on car mechanics but I am trying to do this on the cheap ;).
Any help appreciated.

11 Answers


maybe o2 sensors, take care of the misfire first


OK. I tried replacing plugs and plug wires but no improvement. What would I do to go about checking the O2 sensor? Or is it something you just replace and hope it fixes the problem?

2 out of 2 people think this is helpful.
Tom Demyan

Did you scan for codes after you changed the plugs? What codes come up now?....http://wiki.answers.com/Q/What_does_DTC_P1621_mean_on_a_2001_Chevy_cavlier_mean_and_how_to_fix_it

1 out of 1 people think this is helpful.

I cleared the codes after changing the plugs and no codes have come up again yet.


but how is it running now?? usually removing the codes can be done by removing the neg. batt. cable for a min. it will come back if it wasnt fixed.

1 out of 1 people think this is helpful.

Still not running good. Perhaps a little better as it will occasionally idle in park without sputtering but still has issues under 2000 rpm.


what codes popped up, it could be many things, one leads to another. did you change the plugs with the wires or at least inspect them, if it just does it at idle icm on throttle body, need a better description of what and when

1 out of 1 people think this is helpful.

sorry missed you replaced plugs


Yeah. I cleared the codes with the reader...I was thinking they would come back if they weren't fixed but they haven't yet only put on a few kms though so I will get back to you on that. It is most obvious at idle (only in drive) but also when accelerating until you hit 2000-2500 RPM. Does not sputter when in reverse, only in drive.


because its under a load in drive, does it do it after the 2500 or under hard acceleration. see if you can hear a hissing sound with engine running could be vacuum leak, u-tube has some great help videos im working on my daughters car it has a gremlin i cant find, just keep looking and searching forums. icm on throttle body ??

1 out of 1 people think this is helpful.

Thanks for all your help. Sorry for the late response. I have been very busy and haven't had much time to work on it. It is showing P0300 again. I will check for the hissing sound. I haven't noticed...but then again I haven't been listening for it.

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