94Z Runs rough intermittently.
Thread Starter
Registered User
Joined: Jun 2002
Posts: 548
From: Mantua, NJ, USA
94Z Runs rough intermittently.
I've got a strange one for you. My 94 Z28 started bucking/missing/backfiring and losing power suddenly in traffic. After sitting for an hour or two, it ran fine but I did not test it at WOT. The only thing I did besides let it cool down was manually move the EGR valve because I thought it might be sticking. Car has 220K miles but runs great! The car sat for another 4 hours and then I attempted to drive it about 25 miles on highways. Near the end of the trip, I tromped on it and the problem came back.
The car starts to lose power and starts bucking and wheezing and backfiring. When I finally come to a stop it stalls. I can get it to start but it still exhibits the same symptoms.
There is a trouble code and I am in the process of obtaining a cable so I can use Freescan to retrieve it. What ever happened to being able to flash the SES light!?!?
Does this problem sound familiar to any of you? Any ideas of where to look? I am just getting started because my OBDI cable hasn't arrived yet.
The car starts to lose power and starts bucking and wheezing and backfiring. When I finally come to a stop it stalls. I can get it to start but it still exhibits the same symptoms.
There is a trouble code and I am in the process of obtaining a cable so I can use Freescan to retrieve it. What ever happened to being able to flash the SES light!?!?
Does this problem sound familiar to any of you? Any ideas of where to look? I am just getting started because my OBDI cable hasn't arrived yet.
Last edited by SweetZRag; Feb 5, 2003 at 12:36 PM.
Thread Starter
Registered User
Joined: Jun 2002
Posts: 548
From: Mantua, NJ, USA
I did replace the harness connector for the MAP sensor a few months ago but I was very careful about protecting the splice. I am trying to understand why it would suddenly reoccur when I stomped on the throttle at 60MPH. Now it won't run correctly at all. Hopefully the trouble code will confirm your idea.
I am stumped. Thanks for the idea.
I am stumped. Thanks for the idea.
Thread Starter
Registered User
Joined: Jun 2002
Posts: 548
From: Mantua, NJ, USA
The Optispark went bad (2nd one).
Well it turned out to be the Optispark again. The optical sensor went bad and stopped producing the high resolution signal. I was a little mislead because the TC (thanks Freescan!) said no input to the coil pack so it looked at first like the ECU had gone bad. I then started getting a missing low res signal but it finally settled on just the missing high res signal.
A quick lvoltage check of the input to the Optispark confirmed that that it was bad. I got 225K miles on her and I am averaging a little over 100K per Optispark. Definitely a wear out item.
Unfortunately I already upgraded to an LT4 cam but didn;t convert to the vented Optispark. I was tearing that apart again!
FOr the next 100K mile Opti replacement, does anybody know if MSD makes a direct replacement for the Optispark?
A quick lvoltage check of the input to the Optispark confirmed that that it was bad. I got 225K miles on her and I am averaging a little over 100K per Optispark. Definitely a wear out item.
Unfortunately I already upgraded to an LT4 cam but didn;t convert to the vented Optispark. I was tearing that apart again!
FOr the next 100K mile Opti replacement, does anybody know if MSD makes a direct replacement for the Optispark?
Thread
Thread Starter
Forum
Replies
Last Post