99GrandAm #1cylinder cold misfire-30secs-Cold

[grandam99]

I have a on going problem that I have not seen any prior solutions mentioned in my using the search mode of this forum. Maybe someone here can offer some possible ways to go or look at this in a different light. Here is my problem:
__________________________________________________ _____
1999 4-dr GrandAm Se-1 with V6 Eng./full power accessories ect.
127,000 miles

#1 cylinder misfire code no others codes ever developed or shown
__________________________________________________ ______

(1) Several weeks ago I started getting a service engine soon light , (the one on left side of Instrument cluster panel ect.). The car still ran great and no problems detected as of yet at that time.

(2) Then I noticed it was running rough on cold startups during the first minute of starting and idling like it was running on 5 cylinders per say but this happened ONLY when it was cold and only during the first 30 seconds to 1 minute or so, then the roughness and or misfire goes away and it runs smooth and fine.

(3) The car has been driven through all the paces from 0 to 85 miles MPH, hard accelerations and stops and no missing, roughness or problems ever and fuel economy is great and no other problems have been noticed or found.

(4) The codes were checked and only thing that comes up is #1 cylinder misfire constantly comes back even after clearing codes and service engine light was reset ect. The light doesn't always immediately appear but does stay on for a couple trip cycles then will clear on its own then come back later during one of these "Cold Misfire Startups."

(5) We have changed the plugs as they were in need of them and it did seem to run better over all and the fuel filter was changed and at the same time two bottles of a good Fuel Injector Cleaner has been run through the system and along with a couple tanks of good octane fuel. EVen after all this the probelm still persists but like I said ONLY when cold and Only duirng the first minute or so then totally goes away.

The wires & engine and all else has been looked over several times by several so called experts and the local dealer hasn't found anything to pinpoint what it might be even though they have the latest equiptment. It has been suggested to change out the #1 fuel injector for most seem to think this is the problem and all injectors are the factory orginials and have 127,000 miles and several years on them now. Its a definte cold thing problem and the car runs great but this is something I would like to fix just to ensure its not gonna lead into a bigger problem later on possibily. Any help or suggestions from anyone would be greatly appreciated.

GA99

[fluffybunny]

i see you said the wires looked good, but have they been recently changed, id have them changed just part of regular maintenance, could be the injector, but its up to you wether or not to go ahead and replace it....your call could go either way since it appears to run ok when warmed up a bit....im not too sure but try switching the injector out say with the #2 and see if the problem develops on that cylinder, only other thing i can think of would be the coil and i suppose you could swap that over and see if a problem develops on that cylinder..... could help narrow the problem down without having to buy anything....good luck

[catback23]

misfires are usually an ignition problem. you would have to look at your spark plugs and test the spark to determine if its in the ignition. Also you could be right and it could be your fuel injector, if it's sticking it would take awhile to open after sitting. Really your mechanics should have this fixed by now. And the dealer couldn't fix it? Shows you what dimwits work there. Fine automotive schooling, All the tools DIY'ers wish they had in their garage, and still no power to the light bulb tsk tsk tsk.

[dcs574]

Hello, I am having the same problem, did you find a solution to the #1 cylinder misfire? Mine is happening right now, 82 degree tempertures, and is an ungoing problem. I have the injectors cleaned and so on, I've tryied additives, nothing seems to work.

[MIKLYN]

Hi, I am having the same problem, I have replaced all my fuel injectors, my spart plugs and wires.
I am getting the code for #5 but when they do a more detailed diagnostic the code goes away. It will run fine for about a week then i go to start it and it runs like it is only on 5 cylinders the service engine light comes on and then it runs fine.
Have you had any luck in solving your problem?

[dcs574]

Hey, I ran injector cleaner and so on, change gas stations. Pontiac said try BP or Clark, at least in my area. After a couple days, the miss cleared on its own. But now this morning it started to miss, but I gave it a hard acceleration, and it cleared. Sounds like Pontiac needs to recall these?

[missliad]

my 99 ga has same problem, currently getting plugs, ignition coils and wire set and fuel injection flush from dealer. my car would start up then die out, I had to press on accelerator to rev engine up...was idling rough at stops, but never died out while running...dealer said there were codes that came out that might have shown transmission problems, but went away...they suggested just the plugs, coils, wire set and flush.

[dcs574]

So how much is all this going to cost you? Let me know.

[grandam99]

>>>Update<<<
after changing the old wire set and the #1 fuel injector, my problem has gone totally away. It was time for new plug wires anyway after 127,000 miles on them but seems the fuel injector tested good but during the first 30 seconds of first being cold it would "ACT UP" and caused this code to develope. Like I said it was only when cold start first time of day or after setting for a few hours after running it would do this and only during the first few seconds or so after the start.

Other then that it was fine under all other conditions and loads. Very strange thing but it has gone 500 more miles now sinse the change out of the wires and injector and no codes or return of the problem. This seems to be a rare event for this injector to "Behave" like this ,so it seems, and I was told, but todays electronics and computer controlled cars and engines can develope some of the strangest "Grimlins" we have ever seen and yet to see if you ask me....can't hardly wait till we having more computers and things controlling it all in future cars to be.

We may all have to have a laptop soon as an "OPTION" to be bought when we buy any future cars just so we can have something to tell the dealer....technology....gotta love it. Oh for the old days of a simple chevy 283 with a holly carb.

[dcs574]

I changed all plugs, but car still acts up. A quick acceleration, and it cleared. I think I will most likely have to change that injector.