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Where to even start?

N

NDT

New member
Good Morning All,

Here is a little background on the car:

2000 GTP Coupe
1698XX Miles
New Transmission at 158XXX
LIM Gasket and all that jazz at 155000.
Modified Exhaust- K&N Intake Kit

I was helping a friend roof last friday and I had a ten mile drive home. Five miles into the trip the check engine light comes on, and the RPMs raise to 2k and stay there. I cannot get it to slow down with out neutral, or riding the brakes. It did this for two blocks, then it would not accelerate over 30mph or 2700ish rpm. It runs rough, not drivable, and will die if you hit 31 mph, then start again once you slow down to 15ish mph. it is the strangest thing. There is also a little black smoke when it starts to run rough. The CEL showed MAF and Knock Sensor codes. replaced the MAF, no fix. Unplugged the MAF, no fix.

Does anyone have any pointers? Thanks for the help folks,

Josh
 


What codes specifically did you get?

Maf low input is different than maf totally fubar and getting knock sensor codes seeems to be the thing of the month. Also very odd.
 
I don't know the number of the codes. I will get them shortly. Also, i forgot to add this, It happened twice about two weeks back. The weather was nasty, so i somewhat dismissed it. But after say, 7 miles the car would spit and sputter, then die. I could re-start it, but then had to keep the rpms over 2k to keep running. It was very wet out when it happened, and thought it would go away when it got dry. And the miles leading up to the CEL, it ran just fine.
 
I was thinking it's wiring related so far. Otherwise I wouldnt think it would involve knock sensors and maf ..

Not sure how though. Any battery issues or ground type things happening that you can tell?
 
Not that I can tell. I have a fairly moderate level of engine understanding and this has me floored. I had to move it across the driveway to get the tractors to the fuel tanks, and i started it after a few days, it popped off like it always does, stumbles for a second, then goes to 2k rpms and sits there. I can hear miss on some cylinders. on the way home from roofing, i had to take a stretch of 55 mph roads, i hammered on it trying to get it into second. rpms jumped to 4500, slammed into second, then died. Did that once more, and it stayed running. But would not go over 45 mph or 2500 rpms with out dying. Its got me stumped.

Also for all you geniuses, the car i was driving to work and back is my roommates 02' grand am GT. I drove it home last night, parked it for 5 minutes at my house to run in and grab some stuff to run to town. came back out the there is absolutely nothing happening when you try to turn the car over. The fuel pump kicks on and everything in the ACC mode on the switch. good battery. audio system works. Everything works until you turn the key to the start position. Any ideas? Switch?
 
The GA could be as simple as a loose battery cable or a starter soleniod.

The GP, It's so odd that I'm thinking check battery cables etc, look at the grounds at the lowest bolt/stud on the transmission. The engine speed shouldn't be controlled by anything but TPS or IAC. I've had a bad TPS cause surging/issues and a bad TPS could cause shifting issues. I'm almost thinking pcm and that's not one that I ever suggest. It's that uncommon.
 


I hope its not a pcm. BillBoost, I really appreciate all the pointers. Seriously, i do. Thanks!

If it is a ground issue, how would it still be able to start? Wouldn't the draw be the greatest at start-up? Also, this POS has a bad ignition lock cylinder. I have to access the hole in the bottom of the steering wheel housing to remove my key. Would this cause anything out of the norm?
 
a vacuum leak would cause all this? I knew my gauge not working could be a leak, but it would cause all this mayhem?
 
Could be vacuum related.. and that's a good thing to point out.

Vacuum letting in enough air will cause lean/KR issues. Might also be enough to throw the maf off and think it's faulty. Although.. boost gauge is a small line. MAP sensor issue could also throw things off.

Start by fixing your know issues and let's see what shakes out.
 


So, Here is a little more information for you all,

Went out to look at the car after it had been sitting for a few days. Checked all the fluids, poked around in the engine compartment a little bit and didn't see anything out of the ordinary. Climbed inside and plugged in my scanner and found 15 codes, some of them being duplicated. Here they are:

C0450 - Steering Assist Control Actuator Circuit
C0035 - Left Front Wheel Speed Sensor Circuit Malfunction
P0101 - Mass or Volume Air Flow A Circuit/Performance
P0102 - Mass or Volume Air Flow A Circuit no input
P0121 - Throttle /Pedal Position Sensor A Circuit Range/Performance
P0332 - Knock Sensor 2 Circuit Low input (Bank 2)
P0730 - Gear Ratio Incorrect
P1810 - Tranmission Fluid Pressure Valve Position Switch Circuit

Cleared the codes and started it up. Ran rough for about a minute then she settled down. I then took it for a few mile test drive and all seemed well. headed up to visit my parents about twenty miles away and made it eight miles before she acted up again. pulled in a parking lot, let her sit for a minute, cleared the codes, and drove home. the list of codes generated after it misbehaved was as follows:

P0101 - Mass or Volume Air Flow A Circuit/Performance
P0102 - Mass or Volume Air Flow A Circuit no input
P0121 - Throttle /Pedal Position Sensor A Circuit Range/Performance
P0332 - Knock Sensor 2 Circuit Low input (Bank 2)

Any input is greatly appreciated.
Josh
 
i sprayed some of the vacuum line connections on the top of the motor with no avail. where are the suspect areas?
 


not sure if you still have this issue but if you do id check the igniton fuses, i had a problem somewhat like yours and it ended up being o2 sensor wires melted blowing the igniton fuse causing the idle to go crazy and what to idle down the road at around 30.
 
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