Car hesitating p0171 174 po 420 430
06-01-2014, 10:55 AM
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Car hesitating p0171 174 po 420 430 so the car is a 99 z28. mods slp intake,pulley,exhaust w/ cutout option, predator tune. about two weeks ago i got a tank of bad gas. the car was hesitating terribly but idled fine i had no option but too run the gas through then refuel. the car was better for a few days then some slight hesitation. i added some fuel injector cleaner but no luck. it happens every few days the car runs fine for some time then it goes back to hesitating. the codes it throws are for po 171,174 running lean in bank 1 and 2, and po, 420,430 something with the o2 sensors. today the car did not start on me for about 30 minutes. i was able to get it started and drove it to a local shop. im thinking maybe my injectors or fuel filter are clogged. or could it have something to do with having the cut out and the 02 sensors are not working properly. mind you i dont keep the exhaust open all the time.i was in the process of getting some tools to clean my maf today since i just moved to another country and i dont have anything with me. and when i came back to my car from the store it took 30 minutes to get her to run so shes at the shop now. any help would be great thank you.
06-01-2014, 11:10 AM
#2
sounds like the shitty gas took out one or more O2 sensors. ive had O2's go bad and just throw a code...and then Ive had them go bad and as soon as the car warms up and hits closed loop (this is where car using O2 sensor readings), it will cycle through stages of running like crap every few minutes.
BTW, actually sounds like multiple issues but start with the O2 sensors.
BTW, actually sounds like multiple issues but start with the O2 sensors.
06-01-2014, 11:29 AM
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sounds like the shitty gas took out one or more O2 sensors. ive had O2's go bad and just throw a code...and then Ive had them go bad and as soon as the car warms up and hits closed loop (this is where car using O2 sensor readings), it will cycle through stages of running like crap every few minutes.
BTW, actually sounds like multiple issues but start with the O2 sensors.
BTW, actually sounds like multiple issues but start with the O2 sensors.
06-01-2014, 04:17 PM
#4
shitty gas can cause it to run lean.
running excessively lean or rich can cause them to go bad. there is some debate as to which condition is worse for them. cheap, shitty O2 sensors also don't help the situation (not saying that you have cheap ones).
.
running excessively lean or rich can cause them to go bad. there is some debate as to which condition is worse for them. cheap, shitty O2 sensors also don't help the situation (not saying that you have cheap ones).
.
06-02-2014, 07:48 PM
#7
the O2 sensors nor the MAF would cause the engine not to start... causing "it took 30 minutes to get her to run".
my guess is a lot more is going on compounding your problems.
how do you know you got bad gas? bad gas would cause horrible performance and misfires and misfire codes, not just P0171/4 and P0420/30. and getting bad gas to where it causes problems is quite rare, along with the fuel filter ever being a problem.
my guess is a lot more is going on compounding your problems.
how do you know you got bad gas? bad gas would cause horrible performance and misfires and misfire codes, not just P0171/4 and P0420/30. and getting bad gas to where it causes problems is quite rare, along with the fuel filter ever being a problem.
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06-03-2014, 04:34 AM
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the O2 sensors nor the MAF would cause the engine not to start... causing "it took 30 minutes to get her to run".
my guess is a lot more is going on compounding your problems.
how do you know you got bad gas? bad gas would cause horrible performance and misfires and misfire codes, not just P0171/4 and P0420/30. and getting bad gas to where it causes problems is quite rare, along with the fuel filter ever being a problem.
my guess is a lot more is going on compounding your problems.
how do you know you got bad gas? bad gas would cause horrible performance and misfires and misfire codes, not just P0171/4 and P0420/30. and getting bad gas to where it causes problems is quite rare, along with the fuel filter ever being a problem.
06-03-2014, 08:49 AM
#9
unless you took a large sample out of your gas tank and actually found bad gas, from what you say is not conclusive proof that you had bad gas. that's almost like saying I got in your passenger seat, you started the car it ran terrible, i got out and you restarted and it ran fine, the only thing that happened was I was in the car so i must have been the problem... my point is be careful how you draw conclusions based on limited observation.
06-03-2014, 01:13 PM
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unless you took a large sample out of your gas tank and actually found bad gas, from what you say is not conclusive proof that you had bad gas. that's almost like saying I got in your passenger seat, you started the car it ran terrible, i got out and you restarted and it ran fine, the only thing that happened was I was in the car so i must have been the problem... my point is be careful how you draw conclusions based on limited observation.
06-04-2014, 09:16 AM
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man idk who to believe anymore i was just in contact with the guy i purchased the car from a little over a month ago and said right before he sold it to me he upgraded the fuel pump to a granetelli MS fuel pump right before he sold it to me and he says that he thinks the shop is trying to pull a fast one on me. while the shop is saying that the fuel pump looks old and malfunctioning sometimes which is why im getting the hessitation. idk what to do
06-04-2014, 12:15 PM
#12
a fuel pump is somewhat unlikely to cause your car not to start,
if you turn the key to run you can hear the fuel pump cycle,
if it does then you most likely have enough fuel pressure in the injector rail to start the engine and have it run for 5 or more seconds. checking fuel pressure with a gauge off the injector rail is very easy and would immediately tell you if the fuel pump for the most part is working prior to starting the engine. however once running and driving around if you have a bad electrical connection or something and the fuel pump quits in and out then that would cause the running problems you describe. unfortunately it is not that easy to rig up the fuel pressure gauge so you can see it while driving when the engine is using fuel unlike in neutral. you need someone or a shop with a decent hand held scanner or better to monitor real time data to diagnose things, you'll want to monitor fuel trims, O2 sensor switching, MAF, and so on. my guess based on the mods you mentioned the motor might have seen some abuse, I would do a compression check before putting any money into it.
if you turn the key to run you can hear the fuel pump cycle,
if it does then you most likely have enough fuel pressure in the injector rail to start the engine and have it run for 5 or more seconds. checking fuel pressure with a gauge off the injector rail is very easy and would immediately tell you if the fuel pump for the most part is working prior to starting the engine. however once running and driving around if you have a bad electrical connection or something and the fuel pump quits in and out then that would cause the running problems you describe. unfortunately it is not that easy to rig up the fuel pressure gauge so you can see it while driving when the engine is using fuel unlike in neutral. you need someone or a shop with a decent hand held scanner or better to monitor real time data to diagnose things, you'll want to monitor fuel trims, O2 sensor switching, MAF, and so on. my guess based on the mods you mentioned the motor might have seen some abuse, I would do a compression check before putting any money into it.
06-04-2014, 03:25 PM
#13
Your cats are bad. You need to gut them they are clogging up your exhaust.
You should also look for vacuum leaks and exhaust leaks but 420 and 430 are your secondary 02 sensors and I would just eliminate that problem and get rid of the cats
Fuel pump going out would cause the rpms not to climb, and wouldn't throw any codes. The codes your showing are saying you are having an air problem not fuel
You should also look for vacuum leaks and exhaust leaks but 420 and 430 are your secondary 02 sensors and I would just eliminate that problem and get rid of the cats
Fuel pump going out would cause the rpms not to climb, and wouldn't throw any codes. The codes your showing are saying you are having an air problem not fuel
Last edited by chrysler kid; 06-04-2014 at 03:32 PM.
06-05-2014, 05:01 AM
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Your cats are bad. You need to gut them they are clogging up your exhaust.
You should also look for vacuum leaks and exhaust leaks but 420 and 430 are your secondary 02 sensors and I would just eliminate that problem and get rid of the cats
Fuel pump going out would cause the rpms not to climb, and wouldn't throw any codes. The codes your showing are saying you are having an air problem not fuel
You should also look for vacuum leaks and exhaust leaks but 420 and 430 are your secondary 02 sensors and I would just eliminate that problem and get rid of the cats
Fuel pump going out would cause the rpms not to climb, and wouldn't throw any codes. The codes your showing are saying you are having an air problem not fuel