Start if I hold gas pedal to floor

CHAZ1983

MEMBER
1997 PONTIAC SUNFIRE
120,000 MILES

1997 Pontiac Sunfire stalled on the way home an won't start it does fire up if I hold gas pedal to floor but it barely runs at low Rpms for 30 seconds than stalls I have 42 psi fuel pressure 150 psi compression in all 4 cylinders an have good spark I so far tried a new ignition modular new coils new crankshaft sensor new fuel pump also have tested injectors with noid light an they work fine an even after all the new parts I tried it still does the same thing as originally I'm a good do it hassle kinda guy if only I knew what's wrong with it I can't afford to put it in the shop I ran a obo2 an it said ignition coil module 24x red circuit too many pulses that why I tried all the parts I had I would greatly appreciate any help this is my only car an need it back on the road soon.

Thanks :-)

7 Replies

JACOBANDNICKOLAS

MECHANIC
109,700 POSTS

If you have good spark, good fuel pressure. You should check timing and check to make sure engine compression is good, and check to make sure the fuel injectors are getting power.

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Tuesday, February 7th, 2012 AT 3:33 AM

CHAZ1983

MEMBER
39 POSTS

Allready checked comprssion an injectors as mintion in my first message Got 150psi compression in all 4 cylinders so that's good an did the noid test for I injectors so that's good haven't checked timeing chain sent got compression an it starts buy it just stalls Within 30 secs

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Tuesday, February 7th, 2012 AT 5:25 AM

JACOBANDNICKOLAS

MECHANIC
109,700 POSTS

If it is stalling within 30 seconds, either you are losing spark or fuel pressure.

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Tuesday, February 7th, 2012 AT 7:43 PM

CHAZ1983

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39 POSTS

When checking fuel pressure it stayed at 42psi an I also tried a new fuel pump because I thought that was the problem at first which wasn't I then got a obo2 to check for codes an I got a p0121b which is tps an a p0335 which is crankshaft sensor also the oboe said ignition coil modular 24x red circuit too many pulses I change crankshaft sensor an tps an cleared codes an all that comes back is ignition coil modular 24x red circuit too many pulses I truer a new ignition modular an coils an still no change also had my ignyion muddle tested an it passed as good so basically waisted my money on coils an module so do u got n e ideal what my car needs done about only thing I haven't checked is timing chain but it has compression an does hard start with pedel to floor even tho I have to hold it to the floor just to keep it runing ruff at low Rpms till it stalls

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Thursday, February 9th, 2012 AT 7:57 AM

CHAZ1983

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39 POSTS

Please do you have any ideal on what to try next im out of ideals obo2 only shows one code and it says p0121b with a definition next to it which says ignition coil module 24x red curcit too many pulses what confuses me tho is when I looked up p0121 is says throttle position sensor preformance problem the obo 2 is the state of art on worth a few grand my auncle the head mechenic at middle creek garage an he borrowed it to run on my car wonder why the obo2 says p0121b is a igntion module issue an online it shows a tps now thats confuseing but sure hope you can help me
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