[Biskit118]

Hello, I have been here before for help, but this time I come with something completely different. About a month ago, I was doing maintenance of my truck (i.e., Brake lines and such). I have replaced the fuel filter (hadn't been replaced in a long time), spark plugs, spark wires, vacuum lines from the top of the block, and I have cleaned the fuel tank as well because it had bad fuel in it. There was no rust found in the tank. I have no idea at this point why it is still misfiring. I have eliminated the possibility of it being the ignition coils because all of the cylinders have amazing spark. I am wondering if the fuel injectors are the reason for this. What else could I check? I am not super knowledgeable about how to read a basic obd reader. I have read the codes and only one shows is a PO303. I erased the codes and just letting it idle for a bit turned the code back on. What can I do?

 

[Recklessabandon]

If you suspect an injector issue, I would check for injector pulse on cylinder 3. If you have good pulse, I would swap the cylinder 3 injector out with another cylinders injector, and see if the misfire moves. If it follows the injector, you have a bad injector, if the misfire stays at cylinder 3, you need to look for something else.

 

[Biskit118]

If you suspect an injector issue, I would check for injector pulse on cylinder 3. If you have good pulse, I would swap the cylinder 3 injector out with another cylinders injector, and see if the misfire moves. If it follows the injector, you have a bad injector, if the misfire stays at cylinder 3, you need to look for something else.

How would I check for an injector pulse?

 

[Recklessabandon]

Easiest way is to use a noid light. You can rent or buy them from any auto parts store. When it's misfiring, unplug the injector and plug in the noid light. The noid light will flash when you crank the engine (or it's running) if you have pulse. They will look something like this.

 

[Biskit118]

Would it be worth doing a compression test before using a noid light?

 

[aitch]

Would it be worth doing a compression test before using a noid light?

Noid test first.

 

[Biskit118]

Noid test first.

Why would you recommend a noid light before compression.

 

[Rhotpursuit]

Either or...not like it makes a lot of difference.

 

[aitch]

Why would you recommend a noid light before compression.

Because that's where I would start, w/ electrical check first over compression, with a misfire code reading.

 

[Recklessabandon]

Why would you recommend a noid light before compression.

Of course you could do either one, but originally you suspected injector issues not compression issues. You could do both in 10 minutes.

 

[Biskit118]

Of course you could do either one, but originally you suspected injector issues not compression issues. You could do both in 10 minutes.

How long does it usually take to get to the injectors them selves.

 

[Recklessabandon]

How long does it usually take to get to the injectors them selves.

To check for pulse you only have to unplug the injector electrical connector.

 

[ScottyV1966]

How long does it usually take to get to the injectors them selves.

If your 2.2 is all stock it's going to take about 40 minutes to get to the injectors. (Air Intake Tube, Throttle cable, top intake plenum with vacuum assy. ) PITA! The Fuel Pressure Regulator has a screw down on the Passenger side of the Intake that you will need to loosen or remove to get the injector retainer off. The Injector Wire harness is routed in between the intake "runners" and the fuel rail portion of the intake manifold.
One would think that a 4 cylinder engine would have all kinds of room around it to get your hands on the things you need to reach! Once you dive in you will see. watch your vacuum tubes, they could be brittle! they might break easy.
good luck,
Scott

 

[Biskit118]

If your 2.2 is all stock it's going to take about 40 minutes to get to the injectors. (Air Intake Tube, Throttle cable, top intake plenum with vacuum assy. ) PITA! The Fuel Pressure Regulator has a screw down on the Passenger side of the Intake that you will need to loosen or remove to get the injector retainer off. The Injector Wire harness is routed in between the intake "runners" and the fuel rail portion of the intake manifold.
One would think that a 4 cylinder engine would have all kinds of room around it to get your hands on the things you need to reach! Once you dive in you will see. watch your vacuum tubes, they could be brittle! they might break easy.
good luck,
Scott

Thanks a lot Scott. I shouldn't have to worry to worry to much about my vacuum lines as I just replaced them and get some ones that are slightly more durable.

 

[Chasemon42]

Yep those vacuum lines are a pain. The injectors imo are a pain in the butt to get to. Speaking of currently have an injector leaking after I replaced o rings. Suspect it could be the body.

 

[Biskit118]

I solved my issue. While taking a look at my injectors, I looked at my misfiring cylinder spark plug and it ended up not being usable (it was a bad spark plug from factory bc it melted.) After replacing the spark plug and clearing the codes one final time. I have not received another check engine light or any kind of misfiring. Thank you to everyone who helped me.

 

[PeteD]

I solved my issue. While taking a look at my injectors, I looked at my misfiring cylinder spark plug and it ended up not being usable (it was a bad spark plug from factory bc it melted.) After replacing the spark plug and clearing the codes one final time. I have not received another check engine light or any kind of misfiring. Thank you to everyone who helped me.

Curious here as original post stated plugs had been replaced, but Still had misfire. Were you unfortunate enuf to actually have replaced old junk spark plug with defective new in same cylinder..?

 

[Chasemon42]

How long does it usually take to get to the injectors them selves.

Getting to these injectors is a job. Removing the intake plenum takes a 10 mm and 13 mm I believe 6 bolts. Once you get that off three star bolts secure injector plate T30 I believe. The fuel pressure reg has to be free to gently slide injector holder plate out. That's on a 95 2.2.

 

[Biskit118]

Curious here as original post stated plugs had been replaced, but Still had misfire. Were you unfortunate enuf to actually have replaced old junk spark plug with defective new in same cylinder..?

I did replace the spark plugs for maintenance but I ended up getting bad ones from factory. So I ended getting a misfire after changing the plugs.