4DSPNKR

iTrader: (2)

I searched a lot but couldn't find anythig. Hope this is the right place to post this.
Anyway, I just got my throttle body ported and reinstalled it on Saturday. On the way to dinner that night, I could notice a big difference in acceleration and everything ran great. On the way home, it had trouble starting and when I pulled out in 1st gear, it almost stalled because there was just no power there. Now it still has trouble starting, taking off in 1st gear, bucking when getting on the gas, overall loss of power, and occasional popping when it bucks. Now the SES light is on. My friend (a mechanic) drove it and said the popping was from running lean. We read the codes (PO131, PO151, PO174, PO171) and he thinks there is a vacuum leak or too much air getting into the system somehow. Also, we unplugged the MAF and it ran slightly better, but still pretty bad. Any suggestions on where to look for a leak or what else might be the problem? Thanks in advance.

Blackhawk777

Def. a vacuum leak, and as far as running slightly better without the maf, try getting some maf cleaner and use a q-tip on it. Just remember to be VERY careful with it.

4DSPNKR

iTrader: (2)

Any idea where the leak is coming from? All I did was get my stock tb ported and put it back on. I'm pretty sure it isn't the vacuum line that connects to the tb.

teke184

iTrader: (5)

who did the porting? they could have F-ed up and there is extra air getting around the blade.

i just found a vacum leak on the passenger side of the engine, just behind the TB, attaching to a port on the bottom of the intake manifold. i beleive its the PVC tube. the short rubber connector was deteriorated and had a hole.

try that

did a quick pic to show it

crainholio

iTrader: (2)

That's about like posting "What's my gas gauge read right now?"

Your answer lies under your car's hood, not here.

Two things to check:
1.) Vacuum leaks often have an audible hiss when the engine's running, go take a listen.

2.) Vac leaks will make the engine idle higher than spec if they're big enough...is yours idling higher than normal at operating temp?

Or if you have access to a scanner, check your Idle Air Control value and see if it's maxed out. The PCM will be closing the IAC trying to bring the idle down to spec if there's a big vacuum leak.

4DSPNKR

iTrader: (2)

I don't hear any hiss when its running. The idle is still normal until the car starts to show the symptoms stated above, then it will idle way too low (like 400rpm) and sometimes even stall. I'll check the IAC with the scanner, but the idle is the same as it used to be 95% of the time (except when it idles way too low).

4DSPNKR

iTrader: (2)

I asked them if this was possible and they said all that an overported tb could do is make the car idle higher, not run leaner.

I think I am going to see if my friend will let me borrow his MAF and/or TB just to see if that fixes the problem since those are the only things that were really touched during the removal/ reinstall process. Unless anyone else has more input...

4DSPNKR

iTrader: (2)

I hooked up the scan tool and at idle the short term fuel trims are between 10 and 14, at little high is what my friend says. So we sprayed all around the intake system with carb/choke cleaner and they didn't change. When we unplug the MAF, the STFTs go down to 6 to 8. Does this mean the MAF is bad? I don't mind replacing it as long as that is the problem, but I don't want to start throwing parts at it. All help is appreciated!

dpw41285

iTrader: (26)

when you unplug the maf it will go into speed density tune, does the car run and drive fine with the maf unpluged?

4DSPNKR

iTrader: (2)

It will run slightly better, but still pretty crappy (definately not normally).

dpw41285

iTrader: (26)

then its not your maf, i drove for over a year with a bad maf (well i thought it really was just then 10a engine fuse) didnt know it was bad till i went to get the car tuned and my maf was dead in the water... you def have a vaccum leak with thoose codes and what your describing

4DSPNKR

iTrader: (2)

I know it's kind of a vague question, but where are key spots to look for a vacuum leak considering all I did was get the tb ported? I've sprayed all around it with carb cleaner and the STFTs didn't change and idle didn't change. I figure it has to be a pretty big leak to have these symptoms, but I'm just not finding it.

4DSPNKR

iTrader: (2)

Well i decided to check the fuel pressure just for ***** and giggles, and it turned out to be only 28! So we're going to replace the fuel pump now.:ban g: