Need Help Again
 

so if you guys have been keepin up with my story I've been rebuilding my car after sitting for 3 years. The reason I parked it was It had this driveability problem /i ciuoldn't figure out back then, but figured I know more now so could handle it.
The problem is back from hell!!
For the last few days been driving it everywhere just fine. Hard on it slow on it, freeway, city everything. Well today I brought my g/f to go shopping, everythings going good till we pull out of the mall lot and just brrrrrrrrrrrrrrrrrrrrrrrrr!!!!!

What happens is I'll have full power, then out of no where the car will bog out with hardly any power and SUPER slow acceleration. Then stay that way till i park it for a day, next day will drive good f0r ten minutes then brrrrrrrrrrrrrrrrrrrrrrrrrr!

idles low, and stalled once

So luckly had my scan tool in the car and had a quick look

Heres the biggest flex in numbers i got

Car running good:
o2 B1-s2 between 58-100
o2 B1-s1 between 200-800

Car running like ass:
02 B1-s2 between 0-4
o2 B1-s1 between 43-60

So i was thinking its a o2 sensor, but i have no codes or anything like o2 sensors usually do. And never had an o2 sensor cause this major of a driveability problem.

If anyone has any ideas:
and can always get any engine data needed cause i have a scan tool

TPS
MAF

Sounds like the most likely culprits. Whenever you want to check something and see if it's an O2 sensor issue, simply electrically unplug the upstream O2 sensor(s), forcing open loop operation. This will prevent any changes to fueling by the O2 sensor's input, and you'll run solely off the VE tables (and MAF, I guess, I'm not familiar with MAF tunes). If the car runs fine with the O2 disconnected, it's most definitely the sensor. If the issue remains, it's elsewhere.

Pull out that MAF and see how dirty the hot wires are.

Mine was unsaveable, I put in a new one and it acted up. Once it learned it didn't have to ajust that much to a MAF, it was good. (It shift so damn hard I thought the tranny fell out and I ran it over, no lie! :eek:

The TPS could be taking a crap too, Change that first, they are pretty cheap, like $45-$50 bucks

Throttle position sensor maybe..
so just unplug the pre cat sensor and drive it

But forgot to include my list of less than week old parts
MAF sensor
IAC
Coils
Wires
Plugs
Ignition switch
Ignition switch sensor
Fuel pump
Water pump
Radiator
Condenser
PS Pump
LIMG
Belt
Pulleys

Well, sounds like TPS then. Doubt it's the O2, but yep just unplug the O2 sensor(s) closest to the engine. I says sensor(s) because I'm not sure if you guys have one or two upstreams.

(FYI The IAC isn't actually a sensor, it's a valve. It doesn't sense anything, just opens and closes as the computer tells it to depending on RPM and load conditions.)

whoops didn't relize i put sensor after it, but will let you know luckly i have this awesome thing called a parts car haha thanks guys!! this is why aleromod is the shit, been trying to get on here more often to help everyone else out with what i know too.. didn't know i had such a resource in front of me

bad news, still bad driveability

First: unplugged pre cat o2 -no luck
second: replugged o2 and replaced tps and cleaned maf-no luck
third: replaced maf with one out of running gt-no luck
any other ideas?

what about the cat?

Oh, didn't even think of that. Yep, cut off your cat.

so the plan tonight is to replace the ignition module and bypass the cat

replace ignition module and removed cat, its a no go. Only thin i can think of is back in the day when i bought the car before i was a tech the plug on the ignition module was rubbing on the manifold and melting, my uncle replaced it with new wire. maybe its happening again? its the plug on the drivers side on the rear of the module, the little one? anyone know where that leads to it goes down to where i can't see

This is what i got: would that cause my problem when it gets warm?

I'll answer my own question just inn case anyoneever searches this.
the answer is YES
it looks to be a common problem of cps harness melting on exhaust.

The Confirmed fix is to replace harness and re wire

Test Details Hotline Archive # 350825

Confirmed Fix Vehicle Application: 2000 Chevrolet Venture 3.4L 2002 Chevrolet Impala 3.4L, Vin E

Customer Concern: Misfire, bucks, jerks, backfires, stalls while driving. Idles fine.
Tests/Procedures: 1. With the engine in park, rock the vehicle back and forth, watch the wire harnesses and see if it misses or stalls.

2. Inspect the 7X Crankshaft Position (CKP) harness for a rub through by the exhaust. A Purple and Yellow wire go to the sensor from the Ignition Control Module (ICM).

3. Wiggle the connector and see if the engine stalls.
Potential Causes: 7X Crankshaft Position (CKP) Sensor Harness
Wiring Connection

Diagnostic Codes: None
Author: Bill Siegmann
Average Reported Mileage: 109875



Confirmed Fix Summary

Confirmed Fix 4 - 7X Crankshaft Position (CKP) Sensor Harness
1 - Harmonic Balancer



Confirmed Fix Details

Tech Reported Fix Details Confirmed Fix
Steve Norman
April 24, 2009 2001 Pontiac Grand AM, 3.4L, Vin E, Eng Cfg V6 *
Repaired 7X Crankshaft Position (CKP) Sensor Harness
- Found wiring going from crankshaft sensor to ingition module to be touching egr tube. Wiring had melted and shorted out. At times the engine would back fire and stall. Re-routed wiring and installed new loom. 7X Crankshaft Position (CKP) Sensor Harness
Doug Shetron
July 02, 2009 2000 Chevrolet Venture, 3.4L *
Repaired 7X Crankshaft Position (CKP) Sensor Harness — The crank sensor wire was touching the Exhaust Gas Recirculation (EGR) valve tube.
94,500 miles 7X Crankshaft Position (CKP) Sensor Harness
Eric Lewis
July 31, 2009 2002 Chevrolet Impala, 3.4L, Vin E *
Repaired 7X Crankshaft Position (CKP) Sensor Harness
118,000 miles 7X Crankshaft Position (CKP) Sensor Harness
Allan Theimer
November 06, 2008 2000 Chevrolet Venture, 3.4L *
7X Crankshaft Position (CKP) Sensor Harness
106,000 miles 7X Crankshaft Position (CKP) Sensor Harness
Luis Ortega
March 04, 2009 2000 Chevrolet Venture, 3.4L *
Replaced Harmonic Balancer
121,000 miles Harmonic Balancer



- Confirmed Fix - Exact Vehicle Match - Confirmed Fix - Similar Vehicle Match *- Indicates a Similar Vehicle - Not an exact match to the vehicle selected

Can you take a picture of where this is at? Btw you left previous customer data at the end of the post.

heres a pic of where conector plugs in to, then runs to passanger side of motor, can see it from underneath. it plugs in to the crankshaft position sensor 7x, on the block

IF thats not it, and its still having the issue, possibly your EGR valve

/\/\ new egr thanks for the advice tho

Hmm.. thats a tuff one then. Same thing happened to my gf's car about a week ago. We literally ran thru everything possible, and it ended up being the computer

that sucks, but i got a new computer and bcm also. What was wrong with the computer? were you able to just flash it or did you have to get a whole new pcm

In case anyone else searches this, I had a similar problem once: 3400 that would run fine for maybe 5-10 minutes, then bog down and not run real good. Tech checked it out, told me it was the MAF. Put a brand new one on and still the same problem, so returned the MAF. Ended up all it needed was a crankshaft sensor relearn or something like that. Tech told me the MAF was going bad too, but ran fine for me with no codes.