My 91 405 DL has been doing the same thing for quite a while now. Renewing
the plugs and the wires did nothing to cure the problem. Yesterday I
disconnected the O2 sensor and the 'hiccups' miraculously dissapeared.
Now, my question is what could happen to my engine if I keep on driving
without an O2 sensor? I expected to see the CHECK ENGINE light but this
hasn't happened yet.
Thanks,
Radu
>Frank DeWitt wrote:
>
>> Hi
>>
>> I need help with a 405 (8 valve) that is not running right
>>
>> It "coughs" or hesitates for just an instant. This gets more and more
>>
>> frequent and then get's worse and becomes bucking or losing power for
>> .1
>> sec or so. The effect is less at full power and the car idles
>> perfectly.
>> Here is the bad part, It goes away! The first time it did it, it
>> went
>> away for about 2000 mi. Today it did it maybe 4 times in a 150 mi
>> trip.
>> But only for about 15 mi. total. Today the check engine light came
>> on.
>> Stayed on for from a few sec. to a few min. I have tried shutting it
>> off
>> and re starting, let idle, floor it in neutral (to 100RPM short of red
>>
>> line,) floor it in 3rd to 100 short of red line. None of these seems
>> to
>> have an effect. Right this min. it runs perfect.
>>
>> Please tell me yours did that and what was the matter.
>>
>> Thanks