[throwedoff]

I installed these 3 things at the same time on my 1999 GT, and also used some DIY mil eliminators to hook to my rear O2 sensors to make sure I didn't get a check engine light.

Well, after installing all of this, I have severe idle issues. It's very random, sometimes at a stop the car will repeatedly drop to ~200rpm and then rev up to 1500, sometimes it will die completely while doing this. Sometimes it will sputter while driving at 1300rpm. Sometimes I will literally have to floor the pedal to get it to move from a stop, sometimes it is completely fine.

After resetting my computer and driving about 20 miles, my check engine light comes on. I got the codes read at autozone today and this is what came from that:

Code: P1151 -- Please note that the TPS I am using DID come with the plenum I purchased, it is not my old TPS.
Definition:
Accelerator Position Sensor (APS) property malfunction
Probable causes
1.-Open or short circuit condition
2.-Poor electrical connection
3.-Failed APS



Code: P0136
Definition:H02S 12 circuit condition (Heated oxygen sensor bank 1 sensor 2) Can anyone tell me what O2 sensor in particular this is? I know that it is post-cat, but not what side it is on.
Explanation:
The powertrain control module uses the oxygen sensor to calculate the air/fuel ratio in the exhaust.
Probable Causes
1.-Oxygen sensor defective
2.-Fuel system running very rich or lean-check other codes first
3.-Engine misfire condition-repair
4.-Fuel pressure very high or low-fuel pump or pressure regulator


Code: P1131
Definition:
H02S 11 - Indicates Lean- Correcting for over rich condition
Probable Causes
1.-Leaking injector, regulator or excessive fuel pressure
2.-Engine vacuum leak or open EGR valve at idle
3.-Engine mechanical condition
4.-Failed H02S or MAF sensor


Where should I start looking? Could all of these problems be caused by the TPS problem? As I stated, I do have MIL eliminators hooked up, which should work, so I don't know why the O2 sensors would be throwing codes.

[bigbadwollfff04]

Well two of the problems are coming from the throttle body and plenum, but the other one is boggling me!! I really think you need get yourself some sort of tuner, either a SCT Flash or Diablo, they really help you control the amount of fuel, and your idle speed, but as far as the O2 sensor you can shut this off, i shut it off on mine, seems okay so far, but haven't pushed it yet!! Good luck!! STUMPED

[barksdaleammo]

Originally Posted by bigbadwollfff04 Well two of the problems are coming from the throttle body and plenum, but the other one is boggling me!! I really think you need get yourself some sort of tuner, either a SCT Flash or Diablo, they really help you control the amount of fuel, and your idle speed, but as far as the O2 sensor you can shut this off, i shut it off on mine, seems okay so far, but haven't pushed it yet!! Good luck!! STUMPED

+1

[throwedoff]

Originally Posted by bigbadwollfff04 Well two of the problems are coming from the throttle body and plenum, but the other one is boggling me!! I really think you need get yourself some sort of tuner, either a SCT Flash or Diablo, they really help you control the amount of fuel, and your idle speed, but as far as the O2 sensor you can shut this off, i shut it off on mine, seems okay so far, but haven't pushed it yet!! Good luck!! STUMPED

Thanks for the response. I'm definitely getting a SCT xcal2 sometime in the near future, but do you have any suggestions as to what I could do to fix these problems until then?

Edit: Also, what 2 of the problems are coming from the TB/plenum specifically?

[ChrisJ]

Do you use a chip with a tune on it?

P1151 HO2S21 lack of 'switch', sensor Indicates Lean, (This is seen by the long periods of flatlining on the trace on the low reading. A lack of switch on the high side would generate the error P1152)

P0136 Downstream Heated Oxygen Sensor (H02S 12) circuit malfunction (Bank # 1)

P1131 Lack of upstream Heated Oxygen Sensor (H02S 11) switch, sensor indicates lean (Bank #1)

What kind of mils did you use? becuase it sounds like they are not working...

You did put them on the rear 02's right?

And you did not just remove the 02 sensor right? They have to be in there...Even if you do have them turned off in a tune...

[ChrisJ]

Also the problem with the TPS could be that you dont have the voltage just right which can make the car throw codes and run like crapola...

[throwedoff]

Originally Posted by ChrisJ Do you use a chip with a tune on it? P1151 HO2S21 lack of 'switch', sensor Indicates Lean, (This is seen by the long periods of flatlining on the trace on the low reading. A lack of switch on the high side would generate the error P1152) P0136 Downstream Heated Oxygen Sensor (H02S 12) circuit malfunction (Bank # 1) P1131 Lack of upstream Heated Oxygen Sensor (H02S 11) switch, sensor indicates lean (Bank #1) What kind of mils did you use? becuase it sounds like they are not working... You did put them on the rear 02's right? And you did not just remove the 02 sensor right? They have to be in there...Even if you do have them turned off in a tune...

I don't have a chip/cutsom tune. The MILs that I am using are made from the schematic linked to at the bottom of this page: http://www.fordmuscle.com/archives/2...ale/index.php#

And yes, I put them on the rear O2s and did not remove the O2s.

[throwedoff]

Originally Posted by ChrisJ Also the problem with the TPS could be that you dont have the voltage just right which can make the car throw codes and run like crapola...

I haven't checked the TPS voltage, but from what I hear it's pretty simple to check/adjust, am I correct?

The TPS came pre-attached to the throttle body when I bought it, and I haven't messed with it at all.

[ChrisJ]

Yes its pretty easy to do with a voltage tester...

Sounds like your mils are not working...

[throwedoff]

Originally Posted by ChrisJ Sounds like your mils are not working...

Would that cause bad idle problems and also cause me to get horrible gas mileage (I'm talking 12mpg here).

Or, would that be related to the P1151 code (which says it's 'failed accelerator position sensor')

[throwedoff]

Also, I just looked, and the TPS is a Ford TPS, not aftermarket.

[ChrisJ]

It does not matter what type TPS it is...Its about the voltage...

There is a write up on here on how to do a test on them...

ANd yes bad 02's and faulty mils will cause horrid gas mileage...

The bank 1 upstream 02 (thats before the cat) is what could be screwing the gas up...And your car has to be running like $hit right now...

[throwedoff]

Originally Posted by ChrisJ It does not matter what type TPS it is...Its about the voltage... There is a write up on here on how to do a test on them... ANd yes bad 02's and faulty mils will cause horrid gas mileage... The bank 1 upstream 02 (thats before the cat) is what could be screwing the gas up...And your car has to be running like $hit right now...

Oh yeah, definitely running horribly. Would bad mils cause the car to run worse than it would with no mils? I think I'm going to pull them off and try checking the TPS voltage like you guys suggested... Thanks!

Edit: Also, does it look like the upstream O2 could be bad or could it straighten out once I get the TPS and downstream O2 problems worked out?

[neckbonekat]

You may want to invet in a tuner soon than planned. When I put my O/R X pipe on I just turned my sensors off and haven't had any issues yet. I had a similar issue with the rough idle and the cr trying to shut off but that was because I put on a 85mm MAF and my car didn't like it one bit.

[bigbadwollfff04]

check the voltage, and just buy a tuner, should be all good then, shut off the O2 sensors ASAP!!

[zkid01]

Originally Posted by ChrisJ It does not matter what type TPS it is...Its about the voltage... There is a write up on here on how to do a test on them... ANd yes bad 02's and faulty mils will cause horrid gas mileage... The bank 1 upstream 02 (thats before the cat) is what could be screwing the gas up...And your car has to be running like $hit right now...

+1, Listen to this guy he is right on target. One of your MILS is not working correctly.. As far as the TPS..make sure you plugged it back in for one.. then do a voltage check.. its simple. That should solve your problems. And i would deff think about getting a tuner if i was you. Good luck.

[throwedoff]

Ok, I just tested the middle wire of my TPS (with key turned to acc) and it gave 1.03v closed, and 4.67v WOT. Does this need to be adjusted to be exactly .99v or is 1.03 close enough?

[throwedoff]

I got it to right at .98 and it didn't help any. With the motor running, it fluctuated from .6-1.08

[DrHolliday]

Did you check all your vacuume hoses? Sounds like the idling problem could be a leak somewhere or a problem with your IAC sensor on the plenum.... Some one correct me if I'm wrong.

[throwedoff]

Originally Posted by DrHolliday Did you check all your vacuume hoses? Sounds like the idling problem could be a leak somewhere or a problem with your IAC sensor on the plenum.... Some one correct me if I'm wrong.

Sure did, I've looked over all hoses and gaskets multiple times.


Edit: Just bought an impact driver and got the TPS off of my old TB (surprisingly, even with the impact driver it was a pain in the ass to get off). I'll be swapping the TPS out with the other one soon to see if it makes a difference.