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icecats87
08-14-2010, 11:42 PM
Couple days ago i was getting cylinder 6 misfire, and something with fuel injector number 6. so today took injectors out the upper intake manifold gasket was cracked where the 6th injector was, so the injector had a lot of dirt on it. so i took each injector out and cleaned them, also replaced all the O rings on them. and put some BG fuel injector cleaner in. also replaced the intake manifold gasket.

Now when driving it idles alot better and when i go full throttle it defiantly feels like in launches faster, but now when it goes to shift it has a lag or a delay of a second or 2. what would cause this is it because more fuels getting in with the cleaned injectors? also i have a PCM from MPR coming could this fix it?

AleroB888
08-14-2010, 11:51 PM
Couple days ago i was getting cylinder 6 misfire, and something with fuel injector number 6. so today took injectors out the upper intake manifold gasket was cracked where the 6th injector was, so the injector had a lot of dirt on it. so i took each injector out and cleaned them, also replaced all the O rings on them. and put some BG fuel injector cleaner in. also replaced the intake manifold gasket.

Now when driving it idles alot better and when i go full throttle it defiantly feels like in launches faster, but now when it goes to shift it has a lag or a delay of a second or 2. what would cause this is it because more fuels getting in with the cleaned injectors? also i have a PCM from MPR coming could this fix it?

Well, today was a much cooler day than we've had here lately, so the car would feel more powerful for that reason, too. So did the misfires clear up?

The performance PCM may improve the lazy shifts.

icecats87
08-14-2010, 11:56 PM
Well, today was a much cooler day than we've had here lately, so the car would feel more powerful for that reason, too. So did the misfires clear up?

The performance PCM may improve the lazy shifts.

Yeah they did i was getting a code saying fuel injector circuit board open or something like that, also the misfires and think it was because the gasket was cracked by that injectors causing bunch of dirt to get by the injectors. but before this all happened couple weeks ago the car wasn't having shift delays like it is now.

AleroB888
08-15-2010, 12:03 AM
Yeah they did i was getting a code saying fuel injector circuit board open or something like that, also the misfires and think it was because the gasket was cracked by that injectors causing bunch of dirt to get by the injectors. but before this all happened couple weeks ago the car wasn't having shift delays like it is now.

It's possible that the cracked gasket caused a vacuum leak that messed up the MAF reading, which in turn put it in some fail mode which actually firmed up the shifts before. That's kind of a reach, but I wouldn't rule out anything where these computers are concerned. I'd give it a few days, see how it does on a hot day, then swap in the new PCM.

icecats87
08-15-2010, 12:08 AM
It's possible that the cracked gasket caused a vacuum leak that messed up the MAF reading, which in turn put it in some fail mode which actually firmed up the shifts before. That's kind of a reach, but I wouldn't rule out anything where these computers are concerned. I'd give it a few days, see how it does on a hot day, then swap in the new PCM.

Okay hopefully it gets here before Wednesday, otherwise ill have to wait till sept to get it when i come home

AaronGTR
08-15-2010, 01:15 PM
The new pcm will improve shifts somewhat. There is a limit to what it will do though. GM revised some parts in the transmission to improve the 1-2 shift in 2003, and there is also an algorithim in the programming called "transmission adaptive learn" which takes averages over time of sensor readings for RPM, throttle position, calculated engine torque, and some other things. It uses that to determine wear over time on the clutch plates and will reduce shift time and pressure in order to save the transmission. The only way to wipe out those numbers and start over is with a full write of the PCM.

Basically, other than rebuilding and updating the transmission internals, and doing an occasional PCM write with a tuner, there's not much you can do about the shifting. It will always get softer over time.

icecats87
08-15-2010, 01:39 PM
The new pcm will improve shifts somewhat. There is a limit to what it will do though. GM revised some parts in the transmission to improve the 1-2 shift in 2003, and there is also an algorithim in the programming called "transmission adaptive learn" which takes averages over time of sensor readings for RPM, throttle position, calculated engine torque, and some other things. It uses that to determine wear over time on the clutch plates and will reduce shift time and pressure in order to save the transmission. The only way to wipe out those numbers and start over is with a full write of the PCM.

Basically, other than rebuilding and updating the transmission internals, and doing an occasional PCM write with a tuner, there's not much you can do about the shifting. It will always get softer over time.

Okay its just 3 or 4 days ago there was no delay when car was shifting then after the misfire, and dirty injectors cracked gasket after i fixed that all it all of a sudden did this, so i was wondering if it had anything to do with those things

AaronGTR
08-15-2010, 04:59 PM
Well, if it has more power now, yes the PCM will be able to tell that and it may slow the shifts down a little bit to save wear on the trans now that it is putting out more power.

icecats87
08-15-2010, 05:02 PM
Well, if it has more power now, yes the PCM will be able to tell that and it may slow the shifts down a little bit to save wear on the trans now that it is putting out more power.

Well now its misfiring again but the engine light didn't stay on to read the codes so i have no clue whats going on.

AleroB888
08-15-2010, 05:18 PM
Well now its misfiring again but the engine light didn't stay on to read the codes so i have no clue whats going on.

What are you using to scan it?

icecats87
08-15-2010, 05:28 PM
What are you using to scan it?

Code reader from napa, but when i was going to napa engine light was flashing since it was misfiring, i pull into parking lot put it in park and it turned off, so there was no light. when i left about 20 min later kept misfiring and now engine light is on, going tomorrow to scan again.

AaronGTR
08-16-2010, 04:20 PM
Just because the light isn't on doesn't mean there isn't a code still stored in the PCM. You should still check it.

icecats87
08-16-2010, 05:27 PM
Only code was a misfire nothing with fuel injectors now, so i swapped the spark plug number 6 with 3 seeing if it switches and then it will be bad plug otherwise i have no clue whats wrong

AaronGTR
08-16-2010, 08:24 PM
Well, just because you aren't getting a code for the fuel injector circuit doesn't mean that the problem might not still be the injector either. If it was really bad before, just running some fuel system cleaner through it isn't going to fix it. That stuff only does so much. It's not as good as actually taking them out and sending them to get cleaned in a sonic bath, and if the injector is just old and worn out the only fix for it is a new injector. Even if it's firing, if it's still worn/dirty and the spray pattern is bad or the timing and amount of flow is bad, it can still cause a misfire. Especially if it's causing the air/fuel ratio in that cylinder to differ dramatically from the others.