[xtreme 2]

Hoping someone knows what could be causing this.

So When I cold start the car (in the mornings and after work), the car will fire up fire, idle fine, no issues. But if I put in in gear and let the torque move the car, the car bogs and acts weird until I push the gas. If I revv slightly while in neutral, the car will bog for a second then drive fine.

After this initial bog, the car runs great. No CELs or anything.

When I first noticed the issue I datalogged and my Short Term Fuel Trims were all over the place on Bank 1. At the request of my tuner, I swapped O2 sensors and the problem jumped to Bank 2. Bank 1 ran perfect. So I ordered a new O2 sensor and swapped it out. Now both look great.

But the problem persists.

I changed out my fuel filter a few weeks ago. It was a little nasty looking but still had flow. Problem got better for a few days, then started happening again.

Replaced me steering wheel last weekend, and had the battery disconnected for a few hours during this. Put it back together, car drove great with the Keep Alive Memory cleared, but then after a day it started giving this issue again.

It's almost like the computer in open loop cannot tell the sytem to send enough fuel at idle under load. Once I hit the gas it's like it clears the restriction and operates fine.

My fuel pressure is high, like 60 psi for some reason. If I clear the KAM, it will go back to the 35 normal, but if I drive around for a while then come back, it's around 60 again. This should not be.

I found my vac/boost gauge a few nights ago, and need to get some vacuum line to hook it up and see my idle vacuum to see if I have a leak, but visually I cannot find anything. No Exhuaust leaks.

Any ideas?

going to pull my plugs tomorrow and replace if needed. They have about 20k miles on them, so hopefully they are fine. Can't even remember what they are actually...

[dgt_mustang]

I have the same exact problem, same exact symptoms. I have no clue what it is, I was thinking something fuel related by the way it sounds to me but have not confirmed with my tuner, i have the diablo tuner, so i will do a datalog as well, maybe we can compare numbers and see if the same problem is going on here.

[Loki]

Same problem here .. I just thought it was due to a faulty o2 I've had for a while, but dont want to replace. Lol, haven't actually tried to diagnose it..

[Xzavier247]

Yep have the same problem too. Does it feel jerky? When your going roughly 5 mph?

[xtreme 2]

only at start-up. After I hit the gas the first time, I never feel it again.

I had found an exhaust leak when I swapped my mufflers and swapped my o2 sensors. Before that, if I went WOT from a stop, the car would bog for a second and then pick up and go. Glad that's gone.

[Matt.]

Try looking at your fuel filter , fuel pump , vac lines, Iac

[Xzavier247]

Originally Posted by xtreme 2 only at start-up. After I hit the gas the first time, I never feel it again. I had found an exhaust leak when I swapped my mufflers and swapped my o2 sensors. Before that, if I went WOT from a stop, the car would bog for a second and then pick up and go. Glad that's gone.

I used Seafoam before and it cleared that problem up ,after that it felt like kinda instant throttle response for me, but in the long run it not fucking worth it. Carbo gets built up and etc.

[xtreme 2]

yea I have a bottle here. Haven't run it in a while. Poured some in the fuel tank the other day, haven't done the rest yet.

Fuel filter was changed last weekend, IAC cleaned a few weeks ago just routine maintenance, can't really look at the fuel pump, but I have a Supercar pump here that I have been thinking of tossing in just so I don't have to later...

[iPAPKE]

How are your plugs?

[Xzavier247]

Originally Posted by iPAPKE How are your plugs?

You would really feel them misfiring.
And see if the seafom works when used through the vac line?

[xtreme 2]

Yea I am gonna Seafoam and pull the plugs tomorrow.

[Matt.]

Originally Posted by xtreme 2 yea I have a bottle here. Haven't run it in a while. Poured some in the fuel tank the other day, haven't done the rest yet. Fuel filter was changed last weekend, IAC cleaned a few weeks ago just routine maintenance, can't really look at the fuel pump, but I have a Supercar pump here that I have been thinking of tossing in just so I don't have to later...

check your fuel pressure, you can get a gauge that you plug into your fuel line at like auto zone. Just give them like 100 bucks as collateral.

Could also be a loose ground, my car would shutter and bog for a little, and I found it to just be a ground that was loose.

[xtreme 2]

I did fine a few days ago the power wire to my amp had completely loose and was grounding out on the floor board. Glad I didn't start a fire!

Got it tightened back up, and the last couple of days I actually haven't noticed the stumbling issue.

I don't really need a FP gauge, the Diablosport tells me the fuel pressure at the fuel rail. Like I said, last time it was reading really high. Haven't checked it since I swapped the O2s out and reset the computer.