xsports33

iTrader: (1)

This started happening recently. I turn the key and the engine "stutters" sounds like it's about to die, then all of a sudden surges and rev's to about 1600-1700RPMs. I've had the Radix on for about 2 months and it just started doing this. It runs fine once it's been running, this only seems to happen when i first crank the engine. I'm not sure if it's fuel pump related, but my fuel pump is louder than ever. At idle i can hear it whinning/humming and it's louder than my magnaflow (at idle of course). Called Magnuson and they said it's the first they've heard of someone being able to hear their fuel pump.

Anyone have any ideas about the surging/stuttering issue on start up?

1SlowHoe

iTrader: (28)

Not sure on the surging. Sounds like a possible vacuum leak. Any recent changes or work done.
The fuel pump...if you mean the in-line pump then yes, it whines sometimes and sometimes it doesn't. Mine has done that since install. More noticeable when parked running next to a wall, like a drive thru etc....

xsports33

iTrader: (1)

My pump is not inline, its the replacement pump located inside the fuel tank.

There's been no recent engine work done. I thought maybe it had something to do with the weather, but it's gotten warmer not colder. I should clarify that after it surges to 1600-1700 it comes back down to a normal idle and sounds and drives just fine. It's just at start up when it sounds like it's going to die, revs high, then comes back down to normal. It only happens the first time i crank the engine. If i drive around a bit, cut the engine, and then start 'er up again it sounds perfectly normal.

RandomHero

iTrader: (24)

I have the same problem but I am n/a. I think it has to do with your start-up VE table. I know that's what the issue with mine is.

BigTex

iTrader: (16)

Check all the bolts around the top of the Radix manifold that bolt it to the cylinder head. These are know for coming loose after time, which cause boost leak under WOT and if really loose, a vacuum leak at idle.

xsports33

iTrader: (1)

Found this thread in "Tuning", sounds like we have similar problems regarding the hiccup on start up and taking off when the engine is cold. I'm still running the stock tune that came with the Radix with nothing changed except tire size which i reprogrammed for.

https://www.performancetrucks.net/fo...d.php?t=389447

zippy

I've heard of this same problem and yet many causes. The most common that I've found is the throttle body gasket.

Crash Dummy

Check your IAC count. You may need to clean you throttle body if its dirty or just turn the idle screw on the throttle body in 1/2 turn an that should fix it, this is a very common problem.

BlownChevy

iTrader: (20)

2006 is DBW, no screw to turn

Where in so cal are you xsports33? If you are local to LA come on by and I will fix it for ya.

Crash Dummy

My bad almost as funny as you having to reset your misfire codes all the time before that STS install Ha!