When was the last time you replaced the fuel filter?

 

+1 on fuel filter.

It could be a boost leak once warm something expands causing a leak. What plug gap are you running?

 

When was the last time you changed the plugs?

 

In his post he said he replaced plugs wires and coil.

 

Stock plug gap, iridium plugs, never had a problem with plug gap before. Never changed the fuel filter, so I guess that will be next since its cheap lol. Definitely not a boost leak either, car still boosts and holds it while it misfires lol. Vacuum is also good.

 

Can a clogged fuel filter really cause an intermittent problem like this? FYI, I found out that the previous owner of the car changed the filter, so it was done about 18 months ago. Car has probably seen 10K miles since then. I will change it to be safe and let you know how it goes. Thanks guys!

 

Ohhhhh yes it can. I had a very similar problem with my panda when I bought it from a local DSMer. He tried everything, boost leak test, plugs, wires, coil, timing, etc. Funny, it turned out to be a fuel filter. It would sputter almost every time I would begin to hit boost. Caused overheating due to a lean AFRs. Overheating and sputter went away when I changed the filter. It was the only thing I changed.

 

Get rid of the iridium plugs, get your basic NGK BPR6ES plugs from napa, cost you about $8 total. You dont need split fire, quad damage, surging BFG plugs in these cars, you are just wasting money.

 

I bought the iridiums because they were the only plugs oreilly had in stock. Changed the fuel filter, no dice. Car runs great when started cold no matter how long I drive it, but turn it off and let it sit five minutes and it starts up misfiring.

 

By the way, I have run at least 4 different brands of spark plug on my Talon and other than changing the heat range I have seen no difference in any of them. NGK's do seem to last longer though.

 

I have a friend loaning me a CAS and and an ignition module on Friday, can anyone think of anything else that might be causing my problem????

List of things checked or replaced so far:
boost leak tested, plugs, wires, coil pack, fuel filter

 

I hate to say it but I've seen a similar issue when the HG was burnt between 2 cylinders. Have you done a compression test?

 

Well like red said the head gasket but i would also try to replace the injector on number 2 cylinder because it could be sticking open when started hot its worth a shot.

 

Have you ever done the fuel pump rewire? Is it a stock pump? Do you still have the FPS (fuel pressure solenoid)?

 

compression is low (120) but even across the board. Its been the same for the last six months, so thats not the problem. Fuel pump is walbro 255, dont think its rewired though. Dont know if it has FPS

 

I'd do a rewire of the fuel pump. Costs about $30 and should have been done when you changed the pump. Have you removed all the vacuum lines with the exception of the necessary ones? The FPS is on the firewall to the right of the brake reservior. It would have a vacuum line coming from the fuel pressure regulator.

 

All unneccessary vacuum lines are blocked off properly, and the FPS is not connected to the regulator. I will try to do the rewire soon

 

Im also planning on replacing all the injectors soon because I have a set of Evo 560's and I just picked up my 16g from the same friend who is loaning me the CAS and other parts. Problem there is that I have to retune the car when I do that, which will create its own set of issues lol

 

This seems like a misfire maybe but cylinder 1 and 4 on my rebuilt engine seem very rich, 155psi across the board with no leaks. Plug 2 and 3 look brand new Any ideas? Could vacuum leaks cause this? Also car idles at 450 oddly.

 

Sounds like weak spark or a bad coil. 1&4 are related in firing. Could you have the plug wires misrouted?

 

Definitely check your plug routing. Stupid friend of mine mixed up his and it misfired like crazy.

 

something simple to overlook but when mine was acting up it ended up being a loose battery connection, mine would run crappy when cold tho lol

 

Sorry for taking so long to update this, but I replaced the injectors and the car fired up running perfectly. Haven't seen the same problem since, ecxept sometimes on cold starts it will sporadically studder in the first minute or so of driving. It always clears up, however.

Oh and my low compression problem was due to a severely worn set of Web cams that I still need to send back to them. With stock cams compression is back up over 135 on all cylinders.