Help!! GTP stutter fuel problem.....
JDCowboy
04-21-2006, 03:33 AM
I have a 98 Grand Prix GTP with approx. 94K miles. No mods to the engine. I have read thru many of the post and have not found any with a similar discription to mine.
Check Engine light is on off and on. It even began flashing a few times. I dont know if there is any significance there. I believe it is a fuel problem. I replaced the fuel filter and that did nothing. The problem began with an occassional stuttering while pulling a fairly good grade while traveling at cruising speeds. The stuttering seems to start approximately the same time the boost starts. If I down-shift or mash the pedal it overcomes the stutter and seems to take off like it normally should. The problem seems to have grown progressively worse, but is not totally consistant. Some times it does this worse than others. It has grown to even do this from the stand still take offs. Previously I could roast the tires horribly especially with the tract. contrl off. THe other night it would not allow me to roast them on a consistant basis. Any ideas would be great. It feels very similar to one time way back when I got some bad fuel. The car was bucking and snorting, really had me scared. Even now once the car gets going some it picks up acceleration to more of an expected level. Car shifts well and I dont have any adnormal noises.
Check Engine light is on off and on. It even began flashing a few times. I dont know if there is any significance there. I believe it is a fuel problem. I replaced the fuel filter and that did nothing. The problem began with an occassional stuttering while pulling a fairly good grade while traveling at cruising speeds. The stuttering seems to start approximately the same time the boost starts. If I down-shift or mash the pedal it overcomes the stutter and seems to take off like it normally should. The problem seems to have grown progressively worse, but is not totally consistant. Some times it does this worse than others. It has grown to even do this from the stand still take offs. Previously I could roast the tires horribly especially with the tract. contrl off. THe other night it would not allow me to roast them on a consistant basis. Any ideas would be great. It feels very similar to one time way back when I got some bad fuel. The car was bucking and snorting, really had me scared. Even now once the car gets going some it picks up acceleration to more of an expected level. Car shifts well and I dont have any adnormal noises.
GTP Dad
04-21-2006, 06:26 AM
Welcome to AF!!
The flashing CEL indicates that you have a misfire condition. It could be plugs, coils or a wire so check that first as it can cause engine damage if left uncorrected. The second issue sounds like a fuel pump resistor issue. When the boost comes in the fuel pump kicks into high mode. If the resistor is going bad it will not allow the pump to change modes and therefore you will starve the engine for fuel. The resistor is located in the behind the battery on the passenger side of the car. You can also pull the fuel pump relay and bend tab 85 then reinstall the relay. If the resistor is bad this will bypass it and allow the pump to go into high mode. If the stuttering problem goes away then replace the resistor and the issue should go away. Just make sure to correct the misfire condition!
The flashing CEL indicates that you have a misfire condition. It could be plugs, coils or a wire so check that first as it can cause engine damage if left uncorrected. The second issue sounds like a fuel pump resistor issue. When the boost comes in the fuel pump kicks into high mode. If the resistor is going bad it will not allow the pump to change modes and therefore you will starve the engine for fuel. The resistor is located in the behind the battery on the passenger side of the car. You can also pull the fuel pump relay and bend tab 85 then reinstall the relay. If the resistor is bad this will bypass it and allow the pump to go into high mode. If the stuttering problem goes away then replace the resistor and the issue should go away. Just make sure to correct the misfire condition!
wlkjr
04-21-2006, 06:47 AM
When mine was new I had two wires go bad within the first six months. A couple of months later it started skipping again so the dealer replaced the whole set. Never have had another misfire.
BNaylor
04-21-2006, 08:28 AM
Sounds like spark plugs and ignition wires to me at 94K miles. Since you are stock just be sure to use OEM AC Delco Premium Silicone 7mm wires (726RR) and AC Delco spark plugs. Iridium 41-101 or Platinum 41-921.
JDCowboy
04-22-2006, 10:33 AM
Hey GTP Dad,
I think you are onto something. However I am not so good at instructions. I found the relays. There appear to be 2 of them #14 & 15 in the fuse box. Which one do I need to bend. They are both a 5 prong relay. #'d 1-5. I dont understand what you mean by prong 85. Thanks so o much for your help. Can you provide me with a little more specific info though.
I think you are onto something. However I am not so good at instructions. I found the relays. There appear to be 2 of them #14 & 15 in the fuse box. Which one do I need to bend. They are both a 5 prong relay. #'d 1-5. I dont understand what you mean by prong 85. Thanks so o much for your help. Can you provide me with a little more specific info though.
BNaylor
04-22-2006, 10:49 AM
Hey GTP Dad,
I think you are onto something. However I am not so good at instructions. I found the relays. There appear to be 2 of them #14 & 15 in the fuse box. Which one do I need to bend. They are both a 5 prong relay. #'d 1-5. I dont understand what you mean by prong 85. Thanks so o much for your help. Can you provide me with a little more specific info though.
Based on your symptoms it doesn't sound consistent with a bad fuel pump resistor or the fuel pump speed relay not energizing.
But if you want to go through the process of illimination here is a procedure for relay bypass. Relay #14 for a '98 GTP.
http://rmcgp.clubgp.com/fpresistor.html
When a fuel pump resistor is bad or the fuel pump does not switch to the second speed you will know it because the car will stall within seconds or minutes, may not idle and you won't get too far down the road when it does at least not enough running time to get a misfire indication or a flashing SES light. Just my two cents worth. :2cents:
BTW - If you suspect a fuel system problem run a fuel pressure test at the fuel injector rail and make sure it is in specs.
Also the symptom is identical to simply running out of fuel. A SES/CEL light may trigger but it will stay on not flash. A scan will reveal a P0300 random misfire code.
I think you are onto something. However I am not so good at instructions. I found the relays. There appear to be 2 of them #14 & 15 in the fuse box. Which one do I need to bend. They are both a 5 prong relay. #'d 1-5. I dont understand what you mean by prong 85. Thanks so o much for your help. Can you provide me with a little more specific info though.
Based on your symptoms it doesn't sound consistent with a bad fuel pump resistor or the fuel pump speed relay not energizing.
But if you want to go through the process of illimination here is a procedure for relay bypass. Relay #14 for a '98 GTP.
http://rmcgp.clubgp.com/fpresistor.html
When a fuel pump resistor is bad or the fuel pump does not switch to the second speed you will know it because the car will stall within seconds or minutes, may not idle and you won't get too far down the road when it does at least not enough running time to get a misfire indication or a flashing SES light. Just my two cents worth. :2cents:
BTW - If you suspect a fuel system problem run a fuel pressure test at the fuel injector rail and make sure it is in specs.
Also the symptom is identical to simply running out of fuel. A SES/CEL light may trigger but it will stay on not flash. A scan will reveal a P0300 random misfire code.
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