Top swap issue

**Enzo354** · 02-22-2011

Well Ive replaced the MAF, front 02, vac lines, everything I could think of and it still is idling bad and cutting out under heavy load. The idle is jumpy around 600-800 rpm. Its been tuned with all the basics, and now its been smoked for leaks too.
The o2 is reading lean, about 100 and the fuel trims are all very positive, about 16+. Any suggestions on this?

**matt5112** · 02-22-2011

massive vacuum leak.

**01gpgt01** · 02-22-2011

x2 big vac leak

**Enzo354** · 02-22-2011

We have looked everywhere though and there are no leaks. Its getting the right vac/boost and all.

**GAFF** · 02-22-2011

You do have the map off a l67 right

**Bio248** · 02-23-2011

+16.4 LTFTs mean you have a leak in the system somewhere.

**01gpgt01** · 02-23-2011

You could scan Idle air counts anything lower then 45 on a warm engine idle in park is going to be a vac leak

**JoRoW99** · 02-23-2011

The guy who tuned his car on a local forum says its near impossible since he has 20 in hg on his boost gauge.

**01gpgt01** · 02-23-2011

Funny Ive read around 20 even with a vac leak. Like we said +16.4LFT is a vac leak.

**Pure2sin** · 02-23-2011

I don't think you can just say is a VAC leak and that is the only possibility. Obviously that has been checked already. I would recheck your VAC routing and how you did it with the North*. If you have your MAP plugged in I would unplug that and try to run just off the MAF and tuning of the MAF. I would venture to guess is has something more to do with VAC routing than a VAC leak.

**JoRoW99** · 02-23-2011

Enzo said in another thread that once he unhooked the MAF sensor it idled normally.

He also said his fans are constantly on, if that matters.

**Pure2sin** · 02-23-2011

What MAF are you using Enzo?

**GAFF** · 02-23-2011

Have you messed with the fuel pump?

**01gpgt01** · 02-23-2011

Well if the mafs been unhooked and it runs fine then obviously theres an issue. max fueling 99.99 percent of the time its a vac leak. Maf's usually toss off there own codes, as well as 02's. The post also gives no indications as to the mods on the car. So we gotta assume its a basically stock car. But if this issue was started after a top swap and a tune Id think it could be the IFR table, Or the possibility of the car being a 2001 plus and and having no rear 02 sensor.

**JoRoW99** · 02-23-2011

I agree enzo should have included more detail in here...Ik he has headers, ported SC, smoothed heads, and EGR delete.

**Enzo354** · 02-24-2011

Ok Ill get a bit more specific. Its got headers, ported SC and LIM, just gasket matched heads, N*, EGR delete, and thats about it. 3.8 pulley.
I bypassed the BBV, by leaving open the bottom nipple,

LQ4 MAF with tables transferred on. Its a 2000 and has had the front 02 replaced.

**GAFF** · 02-24-2011

hook back up the bbv

**Pure2sin** · 02-24-2011

Why would you hook the BBV back up? Enzo with that LQ4 do you just have your normal wiring going to it?

Or are you using this:

ZZ Performance

I am running the TAC on my setup and its working fine.

You are running basically the same setup as me other than me having a Gen V. You should take a picture of your vac line routing and PCV routing. I am not saying you did it wrong but I just wanna see what you did and how you did it.