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Discussion Starter · #1 ·
Hello, Im fairly new to the site and I have an 03 Isuzu Ascender with the 4.2l. It has 69k on it and I just noticed that in park or neutral you cannot rev it past about 2400rpm. Now, I know its fly-by-wire and its prolly a safety feature as to keep it from overreving, but I just wanted to make sure. Also, it does not climb rpms very fast at all when you do this. It does however seem to drive just fine. Forgive me if this is a stupid question!
 

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Discussion Starter · #6 ·
I have also noticed tonight that when I first started it and took off after it had sat for about an hour, it didnt seem to have any power and hesitated badly upon the first take off. I drove it about 25 miles after that and didnt have any more problems. Could this be a throttle body that needs cleaned? Driving 55 and flooring it, the trans drops a gear and the rpms rev freely to
5k. Just having low rpm hesitation
 

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2002 gmc envoy_sle
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Which sensor can do this if it's bad or unplugged?
That's what I'm wondering. It does look like the previous owner had either an alarm or a remote start installed and subsequently removed before trade-in because I found a bunch of wire taps under the knee bolster when I had to remove the IP but they weren't connected to anything. I also found a pin switch under the hood. I wonder if this somehow has "disabled" the rev limiter function.:confused:
 

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Discussion Starter · #10 ·
I actually just bought the truck a couple of weeks ago so I dont know if anybody hit anything with the converter. I did notice some mud deposits under the truck so its entirely possible. Im going to try to clean the throttle body today and see if that helps. I dont have a CEL on but I plan to also check everything out under the hood such as wire connectors and vac hoses. I have a hard time thinking its the converter as it seems to run fine on the highway at higher rpms.
 

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2003 chevy trailblazer_ltz
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I remember reading somewhere that the computer controlled throttle wouldn't allow WOT unless the rpms were at least 3,000rpm. And the amount of throttle you do get in park wouldn't be enoigh to get you to 3,000. Put it in drive and you can wind it all you want.
 

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2003 chevy trailblazer_lt
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Which sensor can do this if it's bad or unplugged?
That I don't know, but I'd imagine there is a sensor somewhere to detect when its in Park/Neutral or it wouldn't rev past 3krpm in drive, correct?
it is the neutral safety switch

the neutral safety on the transmission on mine went like a year ago and i could rev it up without problem they was no hesitation in the reving either because it did not know it was in neutral ( it was sounded sweet and my truck would twist when i reved it:woot:) but with the switch bad i could not get into 4low because it did not know it was in neutral:worried:
 

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2003 chevy trailblazer_lt
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my dad has a 03 envoy 4.2 and i have an 03 trailblazer 4.2 and our trucks wont rev up past like 2600 rpm in neutral or park maybe gm must have changes something between 02 and 03:undecided
 

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2002 gmc envoy_sle
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Y'know you guys are right. I just went out and tried to rev it and it struggled to get up to about 3 grand in park and about 3500 in neutral with the pedal floored. :duh:
 

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2003 chevy trailblazer_lt
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Y'know you guys are right. I just went out and tried to rev it and it struggled to get up to about 3 grand in park and about 3500 in neutral with the pedal floored. :duh:
learn something everyday
 
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