code 16 low resolution pulse failure
code 64 right oxygen sensor too lean
code 33 map sensor or circuit too high


can anyone help??

car runs rough then when the check engine light comes on it smooths out..sometimes dies and sometimes wont start..then starts like nothing is wrong.

anyone ever had these codes and what was your problem.

thank you
Brad

 

code 16=need new opti.

 

2 things are very interesting about your failures. The first is that while many OTHER brands of MAP's do fail, GM's are practically bullet proof. The other is, the sensing circuits for all the devices you listed are powered by the PCM. This would indicate that you either have a power problem at the many connections to the PCM, or the PCM is defective or there is another problem on the supply line from the alternator.

I would first check the wiring to each of the devices listed for shorts to 12 volts. Then check the alternator for bad diodes by putting a meter on the negative terminal of the battery and the ouput post of the alternator. Have the meter set to AC. Be sure it's not higher than 0.03VAC.

The last thing to look for is power and grounds to the PCM. Some often overlooked grounds are above the starter and near the ICM.

Last thing to check is the reference and ground to the devices in question.

 

IMO, the MAP code is being caused by the engine barely running or dying. Not a MAP fault, but the result of other trouble (like maybe the opti).

 

It's not unusual to find a "stored" DTC 16 on an engine with a healthy Opti. Seems to set when the PCM has trouble finding the low res pulse on startup. Clear the codes and see how quickly that one comes back. It has to be a "stored" code, because if it was active the engine wouldn't be running.

DTC 64 is for Bank 2... check for exhaust leaks, misfires, faulty O2 sensor.

DTC 33 may be due to what Rob points out. I think the MAP at idle has to be over 68kPa to set the code. Who did the tuning for the heads and HOT cam? What is your normal MAP (or vacuum reading) with that setup? If the tune isn't right, and you throw on some misfires and you could be seeing high MAP values. One thing to check, although it usually sets DTC 34 is the harness connector for the MAP sensor. They dry out and crumble and make poor contact with the sensor pins.

How long have you had the problem with running rough? Did it previously run OK with the heads and cam? Have you made any changes at all just before the problem started?

 

well I cleared the codes..the one that came back was the right bank lean code. IF it was the sensor..then why does it not want to start sometimes and then sometimes start fine?sometimes it drives fine..sometimes it drives really rough. After I got the codes cleared it has only thown one code. I have replaced my opti and the harness within the last few months so I agree now looking back those could be stored codes and it was trying to die on the way to the shop to get it scanned so it might have thrown the one code when it was trying to run and then shutting off. So on the right bank lean code.. what things should I look for before changing the o2 sensor? also could it be the other one running rich? mine is a 95 I have heated sensors right? Would these effect the car at startup? or just when they come to temperature?

thank you for all your replys,
Brad

 

oh and PCM4less did the programming and the car has had this problem for awhile now..it seems like I have been chasing a ghost miss or a hesitation that I can never find. What is your advice for me to do next?


Brad

 

Try swapping the O2's side to side.