96 sunfire misfire

[gandy911]

my 96 sunfire 2.2l (check engine light blinks) misfires/idles rough/lacks power on acceleration.
i have checked wires/plugs/replaced both coils and ignition module/checked EGR valve its fine. what else could i check?

[shakewell]

Pull the vaccuum line off of the fuel pressure regulator (it's on the end of the fuel rail) - if there is any fuel inside the vaccuum line, replace the regulator.

[gandy911]

Originally Posted by shakewell

Pull the vaccuum line off of the fuel pressure regulator (it's on the end of the fuel rail) - if there is any fuel inside the vaccuum line, replace the regulator.

Thanks will try that when i get home!!

[KCMike]

Originally Posted by gandy911

my 96 sunfire 2.2l (check engine light blinks) misfires/idles rough/lacks power on acceleration.
i have checked wires/plugs/replaced both coils and ignition module/checked EGR valve its fine. what else could i check?

If the problem with the misfire is there at idle you may have a basic engine mechanical problem. many times these get overlooked while suspecting electrical problems. I would at least check the compression at this point and inspect for vacuum leaks. If you have a vacuum gage is it pulsing? Steady? Let us know and maybe we can walk you through a few steps.

KCMike
ASE Automobile Master Technician
L1 Certified
http://automotiveresource.org

[gandy911]

Originally Posted by KCMike

If the problem with the misfire is there at idle you may have a basic engine mechanical problem. many times these get overlooked while suspecting electrical problems. I would at least check the compression at this point and inspect for vacuum leaks. If you have a vacuum gage is it pulsing? Steady? Let us know and maybe we can walk you through a few steps.

KCMike
ASE Automobile Master Technician
L1 Certified
http://automotiveresource.org

I checked all cylinders and they all had 120 Psi compression. no vacuum leaks anywhere found. you can hardly tell the engine misfires when idling but it does and when driving it isnt rough or anything it just dont have any accelleration power.

[KCMike]

Originally Posted by gandy911

I checked all cylinders and they all had 120 Psi compression. no vacuum leaks anywhere found. you can hardly tell the engine misfires when idling but it does and when driving it isnt rough or anything it just dont have any accelleration power.

It is very hard to tell you anything conclusive without experiencing the symptoms first hand. What you consider rough and what I consider rough may be two different things. From most of my experiences a misfire will create a rough condition, or maybe you could refer to it as an out of balance feeling. The nearest thing I can think of that would make a misfire seem like the engine was not running rough might possible be if a cylinder was misfiring constantly or if a coil pack, module, or many other possibilities were killing more than one cylinder. This would be a difficult thing to test if you have limited eperience.

There are many things that cause a general lack of power though, that have nothing to do with a misfire. Low fuel pressure, or a restricted exhaust for example can cause a general lack of effeciency for all cylinders. You may want to get a service manual that explains the methods of testing for these basic things. It is a process of narrowing down the possibilities and then zooming in on the cause. Very hard for anyone to help without some specific information. But if you are a do it your selfer grab a manual, read some procedures, and post some results. I would be glad to respond if I can help. Good Luck!

[shakewell]

Originally Posted by KCMike

Very hard for anyone to help without some specific information

This

[gandy911]

thanks for the reply, i will get a manual. *update* replaced ignition module and both coils, didnt help. so rule that out.

[KCMike]

Originally Posted by gandy911

thanks for the reply, i will get a manual. *update* replaced ignition module and both coils, didnt help. so rule that out.

I may be wrong, but from what you say so far I get the feeling that this may be something that is relating to all cylinders and a general lack of power rather than a misfire. Do you have a vacuum gage? Or maybe a friend that could check the vacuum at idle, and then at 2500 rpms (approx.). Is the gage reading steady at idle? You should have a steady 18 -20. Much lower or unsteady may give us a clue at least. If you like working on your own car a vacuum gage is a very useful and affordable tool. Vacuum tells a lot about what is happening in your engine. Let me know. Good luck.

[KCMike]

Originally Posted by gandy911

thanks for the reply, i will get a manual. *update* replaced ignition module and both coils, didnt help. so rule that out.

OOOps, I missed one very important clue you already gave. You said in your original post that the Check Engine light blinks. This means that the fault is catalyst damaging. Also it does usually indicate a misfire. Even though you have changed both coils, module, plugs, etc. You still could have lost power to a couple of injectors, or have another fault that would cause a misfire. I have a pretty busy weekend but if I get a chance I will take a look at a couple of things in my service information and post them for you. Maybe someone with a better recall than I can help out sooner! Talk to you later.

By the way, don't drive the car if you can avoid it. This kind of a condition can cause your catalityc converter to fail and cost you more money. It's a bummer I know, but it is a true story.