QuestionQUESTION: 97 grand voyager, 3.3L 2wd. While traveling down the highway the engine suddenly lost power for 1 to 2 seconds and then goes back to normal. The tach dropped immediately to 0 during the episode and then goes back to normal so I'm not thinking it is a dash solder problem but could be wrong. This happened a total of 4 times during a 200 mile trip yesterday. I had the battery and alternator checked at autozone this morning and everything there checks good. Had the codes pulled and got po442 (EVAP small leak), po403 (EGR system fault), and one other but I lost the number that had to do with the heated o2 sensor. Nothing else showed up. These 3 codes have been there for a while but I haven't had money to go after them due to other priorities. The plugs and wires have been changed in the last 6 months and the fuel filter and pump have been changed in the last 12 months. To me it seemed electrical but being as intermittent as it is I could be wrong. Anyone seen anything like this or have a clue where to start looking? Thanks for any help you can send my way.
ANSWER: Hi David,
Of the three, my suspicion would be the 0403 as that involves the egr which if not controlled properly can cause the engine to falter and then recover if it is then corrected. The issue with the code is the wiring between the pcm and the egr solenoid. There is a white/black wire from pin 20 of the pcm to pin 1 of the egr that carries 12v. The activation of the solenoid is handled by a gray/yellow wire from pin 40 of the pcm to pin 2 of the egr. That wire is either grounded or has 12v on it, where that control is exercised by the pcm based upon the MAP and the throttle position sensor. So check those connections, and be sure they are not flaky (shake the harness) or subject to being shorted to ground.
If that doesn't prove rewarding, I would check the function of the egr valve by moving the valve stem, using a screwdriver in the slot of the stem to move it back and forth. If it 'sticky' the spray some WD-40 on the stem where it enters the valve body and move the stem to loosen it up.
The third possibility is that one of the engine rotation sensors is beginning to break dowm. When that happens it will set the code 0720 or 0740.
The evap and the oxygen sensor might be involved but with a lower likelihood. The main problems would be unnecessary air pollution.
That is my thinking based upon what you have described.
Roland
Please 'rate' my answer. And where you see the question abour 'volunteer of the month' please consider giving me a 'yes' vote if you believe I warrant it. Thank you.
---------- FOLLOW-UP ----------
QUESTION: Thank you for pointing me in the right direction. I found one of the pins on the EGR solenoid was broken. I'm headed out to get another one now. I still don't quite understand how this problem relates to the current problem of short term loss of power. The EGR code has been present for over a year and it has never had this problem before yesterday. Someone else suggested the camshaft position sensor caused a similar problem with his voyager but I would think if that was the problem it would set a code for that. I will report back after the EGR is back together. Thanks again.
ANSWER: Hi David,
It would be good to check the 'action' of the egr valve stem, nonetheless. It could be the cam or the crank sensor, but the failure may not have reached the threshold to set a code. So see if cleaning up the egr system helps and let me know if it doesn't.
Roland
PS: Please rate my answer. Thank you.
---------- FOLLOW-UP ----------
QUESTION: The original valve moved freely when tested. EGR valve and solenoid replaced as unit (thats the only way the store had the part). Reset the computer by disconnecting the battery for 5 minutes. Idled and drove for about 15 minutes then had the codes scanned again. EGR seems to be working correct now and the code is no longer there. The O2 sensor and EVAP codes also cleared. Will see if that stays true over the next few days and hopefully will see if the loss of power problem is fixed or not. It did have a code PO300, multiple misfires, after I test drove it but it felt smooth and had more power than normal so I'm not sure what that could be.
AnswerHi David,
Thanks for the report. The 0300 can be almost anything...the list of possibilities to check is overwhelming. So let us see what develops first and go from there when/if codes reappear. I suspect that the evap and the O2 sensor codes will return.
Roland
PS Please rate my answer(s) if you feel like doing so. Thank you.
