Alright, I posted a few weeks ago about an engine miss at idle. Truck was at the dealer for diagnosis. They said it was losing fuel pressure at idle. They did the reflash, the one that adds fuel filter life etc, and then they couldnt reproduce the miss. They also said the fuel filter pulled 5 in. Hg of vaccum and recomended changing it soon, I changed it the next day. That was about two weeks ago, the problem resurfaced today. Lemme give as much background on the miss as possible. It will start to miss after it has been idling for a while (as little as 15 seconds or as much as 10 mins mainly when engine is warmed up). No smoke when it misses, showing to me that it is a lack of fuel issue. I tried pumping the primer while it was missing and it did not change anything. It doesnt miss at higher rpm or have any power loss at higher rpm with one execption. When first starting in the morning (cold start under 32 degrees F) auto fast idle on 1200 rpm, i can here a slight miss, and can feel a slight shudder in the shifter (manual).
Now heres the problem, GM voided my engine warranty (truck has almost 37000 miles on it, however it was brought in when it was still in the 36000 bumper to bumper warranty) when i brought it in for this problem because i have an EGT probe in the exhaust (its the edge egt probe). I am currently talking with GM but they need to talk to the dealer and will call me back tommorow. I plan on fighting this to the fullest because i know that the egt probe or the edge is not the cause of the problem. Edge was not installed when i brought it to the dealer (attitude was in the upper console, its permanently installed) and hasnt been for several weeks now, the miss happens with or without edge.
Now here are my questions, assuming worst case senario, and GM refuses to help me on this problem, what do you guys think it is? Do you think it could be a fuel pump? maybe the bosch fuel control brain mounted on the motor? What tools am i gonna need to diagnose this problem should i have to do it on my own? What should I check for? I dont really know alot about the fuel system in this truck. I dont think it is the fuel wiring harness rubbing through and grounding out problem discussed on here cause it only does it at idle and never has had any other syptoms at rpm (i would think if a wire was shorting out i would have codes and it would have syptoms at any rpm). There are no codes btw. Injector balence rates are all well within the +-4 spec so i dont think its an injector problem. No fuel in oil per last sample.
Any suggestions or help is greatly appreciated, I'm just trying to get ready if I need to diagnose this problem on my own. sorry for the long post, tried to be as through as possible on the problem.
Now heres the problem, GM voided my engine warranty (truck has almost 37000 miles on it, however it was brought in when it was still in the 36000 bumper to bumper warranty) when i brought it in for this problem because i have an EGT probe in the exhaust (its the edge egt probe). I am currently talking with GM but they need to talk to the dealer and will call me back tommorow. I plan on fighting this to the fullest because i know that the egt probe or the edge is not the cause of the problem. Edge was not installed when i brought it to the dealer (attitude was in the upper console, its permanently installed) and hasnt been for several weeks now, the miss happens with or without edge.
Now here are my questions, assuming worst case senario, and GM refuses to help me on this problem, what do you guys think it is? Do you think it could be a fuel pump? maybe the bosch fuel control brain mounted on the motor? What tools am i gonna need to diagnose this problem should i have to do it on my own? What should I check for? I dont really know alot about the fuel system in this truck. I dont think it is the fuel wiring harness rubbing through and grounding out problem discussed on here cause it only does it at idle and never has had any other syptoms at rpm (i would think if a wire was shorting out i would have codes and it would have syptoms at any rpm). There are no codes btw. Injector balence rates are all well within the +-4 spec so i dont think its an injector problem. No fuel in oil per last sample.
Any suggestions or help is greatly appreciated, I'm just trying to get ready if I need to diagnose this problem on my own. sorry for the long post, tried to be as through as possible on the problem.
