I've owned my Grand Cherokee Laredo 10 years I love my Jeep let me explain why!! 2 days before it died while I was driving I couldn't go over 35 when I applied gas it would Studdard backfire and lose power so I went in to investigate I found that the EGR valve module was completely fried on replacing it one of the bolts was loose replacing that I figured that was the problem I got it to run when I applied gas it would die, here's what I figured she's 24 years old time for some new parts so I replaced crank sensor fuel pump coil ECM spark plugs cap Rota wires new vacuum lines PVC valve I'm still getting the same results she starts wants to run it dies when you give it fuel, so I took the throttle body of pull speed sensor indicator motor cleaned everything put it back together runs but dies when you hit gas my question is why won't it run? Could the alarm system have something to do with it? I've checked the code several time I reset it and checked it it's still coding 12 / 55

  • Welcome to Motor Vehicle Maintenance & Repair! If I'm reading the codes right, 12 pops when the battery has been disconnected in the past 50 key offs; 55 pops when the drive cycle hasn't completed yet. Neither of these are going to be an issue with it running. I have no idea about the alarm system. Overall, it sounds like a throttle position sensor isn't working correctly. Also, could you PLEASE edit your question and put some syntax in there. The run on sentence is VERY hard to read. Commented Jan 15, 2018 at 15:18
  • Hey Paulster2, If there was a problem with the throttle position sensor wouldn't that show up on my codes I'm so sick of guessing and I know the alarm kills everything yes Commented Jan 15, 2018 at 15:28
  • No, not necessarily. You can test your TPS to see if it has full range of motion. If the engine doesn't want to run off idle, it would seem to me this is the first place I'd start looking. Commented Jan 15, 2018 at 16:18
  • dying when you give it gas makes me think of fuel pressure. Have you put a pressure gage on it?
    – agentp
    Commented Jan 15, 2018 at 18:02
  • 1
    @sjfklsdafjks I'm pretty sure those engines are speed density and don't use a MAF. OP what is normal fuel pressure? Numbers please. Do a TPS sweep and make sure the MAP sensor reads correctly KOEO and under different levels of vacuum. Are the O2 sensors switching? How about other sensors? You need to stop replacing parts and do some multimeter work. If you don't already have one buy a service manual.
    – Ben
    Commented Jan 18, 2018 at 23:14

1 Answer 1


If you're still having issues with that, I put a fishing weight on my throttle cable. That will keep it idling for you. My 94 is cantankerous too, and in the winter doesn't like the throttle cable cable throttled. Seriously, put a fishing weight on your throttle cable. Works great.

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