3800 Loss of boost/power +100 mph

When I floor the car getting onto the highway and go over 100 mph, the boost will go from 11 lbs down to 4 or 5 lbs. I can feel is stutter a bit also. This will happen when floored and always between 100-120.

What can this be? I have a tune from Ron, could there be a glitch in the timing? Fuel pressure/pump?

Ron, can you shed any light on this, anything I should be looking for to start off with?
 
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imported_silverbullet

Guest
i had kinda similar problem like that. when i done my 3" custome exhaust and pacesetter my car seem slower than when it's stock. when i accelerlated it spudder and if i let off the gas pedal it back fire and making that snap, cracker, pop sound. i was reading like 6lb of boost. it was driving me crazy for a month that's when i ordered zzp pcm having them deleted rear 02 sensor, egr, and evap out. took out the cat too and that makes alot difference no more back fire, accelerate faster, and my boost gauge was up 9+ lb. maybe it's the cat like ron said.
 
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imported_Xerxeis

Guest
I was told there is no governer now.

Do you really think my injectors are maxed?

What's EGT?

And no, my stupid ass still doesn't have a scanner, that is my next purchase for the car once I have some funds.
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Injectors are programmed to shut off at a certain mph and turn back on a few mph less

ie: my GT used to shut off at 108 and come back on at 105
 
Thanks for the input.

I am going to lean towards the injectors, but I'm not gonna screw with them anytime soon. It's not an everyday occurance that I feel like doing 100. Plus I want to make certian that is the problem, once I get my much overdue scanner.

The only way I'm going to get rid of the catalyst protection mode in the PCM is to powertuner it out, correct? How is this code detected, from the rear O2 sensor?

Besides an intercooler, how can I lower the EGT?
 
clogged cats can lead to high EGTs. free up your exhaust. check your fuel system like the filter and such, running lean makes hotter temps everywhere.
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Read my sig, NO CAT.

Thanks anyways Bob, I have changed my filter about a year ago. I could be running lean but kinda hard to tell without a scanner.

Would I be able to check if I'm running lean with just a scanner? What parameters?
 
Besides an intercooler, how can I lower the EGT?[/b]

You don't need to lower your EGT, the computer just thinks you do to save the cat. A parameter in the PCM just needs to be changed. It's the "boost dump" problem that's very common on reprogrammed PCM's.
[/b]

Not sure if you remember but you reprogrammed my car a while ago. I wouldn't know if you took it out or not. The thing runs like a champ except for this issue.
 
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imported_Ron Vogel

Guest
<div class='quotemain'>
Besides an intercooler, how can I lower the EGT?[/b]

You don't need to lower your EGT, the computer just thinks you do to save the cat. A parameter in the PCM just needs to be changed. It's the "boost dump" problem that's very common on reprogrammed PCM's.
[/b]

Not sure if you remember but you reprogrammed my car a while ago. I wouldn't know if you took it out or not. The thing runs like a champ except for this issue.
[/b][/quote]
I probably forgot to change it from stock, I can fix it no problem. A few of the first PCM's I did ended up with this issue. Didn't even know it was a problem until I was trying to diagnose the very same problem. When you change the fueling/spark, it also changes the calculation of EGT's by the PCM, so the parameter needs to be altered.

Shoot me a PM when you're free and I'll re-flash it.
 
<div class='quotemain'>
<div class='quotemain'>
Besides an intercooler, how can I lower the EGT?[/b]

You don't need to lower your EGT, the computer just thinks you do to save the cat. A parameter in the PCM just needs to be changed. It's the "boost dump" problem that's very common on reprogrammed PCM's.
[/b]

Not sure if you remember but you reprogrammed my car a while ago. I wouldn't know if you took it out or not. The thing runs like a champ except for this issue.
[/b][/quote]
I probably forgot to change it from stock, I can fix it no problem. A few of the first PCM's I did ended up with this issue. Didn't even know it was a problem until I was trying to diagnose the very same problem. When you change the fueling/spark, it also changes the calculation of EGT's by the PCM, so the parameter needs to be altered.

Shoot me a PM when you're free and I'll re-flash it.
[/b][/quote]

Thanks Ron! I really appreciate it. I will let you know soon.
 
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