Car seems to be breaking up at 4200rpm...help
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Joined: Mar 2008
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Car seems to be breaking up at 4200rpm...help I have a 95 z28 with full exhaust and cam. The car has been running a little rough lately and randomly takes a couple trys to start. But my main problem is that when i get on it at about 4200-4400rpm it feels lik its not getting any gas and choking up. I changed the fuel filter maybe 500 miles ago. Code 43 mass air flow system failure will come on randomly but turns off within 2 mins. What could my problem be? Any help would be great Thanks
I have a 95 z28 with full exhaust and cam. The car has been running a little rough lately and randomly takes a couple trys to start. But my main problem is that when i get on it at about 4200-4400rpm it feels lik its not getting any gas and choking up. I changed the fuel filter maybe 500 miles ago. Code 43 mass air flow system failure will come on randomly but turns off within 2 mins. What could my problem be? Any help would be great Thanks
I would disconnect your MAF and run the car also, see if it drives any better, and yes, it will run and start with your MAF disconnected.
A bad coil or opti can also cause a high rpm miss...
Same thing mine is doing, i just replaced the wires with MSD's, Newer GM opti, New coil, and new plugs lol. As far as my fuel system thats all new too, BBK 255 pump, New GM Regulator, and 24# SVO's. Mine starts to miss and pop hardcore around 4000+. Pulled a code for a bad ECM and that is on the way so we'll see what that does. But let me know if you find anything and i'll do the same.
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Here is a free lesson.
What it takes for a motor to run.....
1) Fuel
2) Air
3) Spark
4) Compression (for the most part)
5) Computer/Timing (if be it via PCM or old school)
You can test each cyl to see if there is a spark and making sure there is no air blockage, your almost half way there.
Fuel needs to be done via a guage but you need to run it with a load on the motor which means hook it up, feed it through the hood and tape to the windshield and do some WOT runs and see if there is a siginifgant pressure drop.
Compression should be a last alternative but you never know until you start checking.
Computer- if it had a recent adj to the tune, that can be an issue too.
For your situation I vote fuel, probably need a pump. Opti symptoms closely mirror fuel starvation issues. F.Y.I.
What it takes for a motor to run.....
1) Fuel
2) Air
3) Spark
4) Compression (for the most part)
5) Computer/Timing (if be it via PCM or old school)
You can test each cyl to see if there is a spark and making sure there is no air blockage, your almost half way there.
Fuel needs to be done via a guage but you need to run it with a load on the motor which means hook it up, feed it through the hood and tape to the windshield and do some WOT runs and see if there is a siginifgant pressure drop.
Compression should be a last alternative but you never know until you start checking.
Computer- if it had a recent adj to the tune, that can be an issue too.
For your situation I vote fuel, probably need a pump. Opti symptoms closely mirror fuel starvation issues. F.Y.I.
