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Discussion Starter #1
Hello to all . im new to the forum and to the srt8 family. Its already mopar or no car for me ive had all kinds of fun stuff. Always wanted an srt8 specifically the jeep... But this 300 came about in a good deal and i gotta say i love this car. Ive had nicer and faster...but like i said i love this car. The car is n/a on e85 with the srt4 stage1 injectors. I developed a misfire, on cylinder 8 all the coils were good did the plugs for shits and giggles ... The plugs for 8 were black and visibly no good. Every other spark was white as expect with e85. Changed plugs and the car is back to normal. Sorry to say its back. Put it on my scanner cylinder 8 again . swap a coil from 8 to 7 and 7 to 8... Cleared codes ran and scanned it again... Cylinder 8 . well the misfire had gotten worse. Cylinder 6 has now joined in the misfiring party and now like ive read on here before "t sounds like a wrx"... Im leaning toward an injector problem ? I mean the plugs looked rich af. Maybe the o ring ima tear it down in the morning and take a look... Either way if anybody can lend some wisdom and lead me in the right direction and save me some time, id really appreciate it. Thanks fellas
 

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I'm betting you swapped 6 and 8 actually.

evens are on passenger (R) side, odds on driver (L) side

2 4 6 8
1 3 5 7


Might be a bad coil, could be the connector pins on the coil have damaged ( bent) the plug contacts in the harness. Look real close in there--
 

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Welcome to the forum. I am guessing it's an injector problem too. Try swapping those two injectors (6 and 8) with the front two front ones on the same bank (2 and 4). See if the problem moves. You may want to try running some Techron through it (I do it about every 2000-3000 miles) and see if it cleans the injectors and gets them back to normal.

Here's a few random questions to ponder:
--How long have the new injectors been on it and why did you do away with the stock ones.....E85 or ?
--Any problem with the stock injectors or did the start after the new injectors were installed? IMO, unless you have it tuned for E85, you're probably not helping it any. Also, if you let it run REALLY rich for a long period of time you could end up damaging the cylinder walls.
--Have you done a compression and/or cylinder leak down test(s) on it?
--Any other mods. to the engine?
--Any other recent problems/history?
--Are you running the stock spark plug heat range and stock gaps?
--Any exhaust leaks on that cylinder bank?
--Any codes at all? If so what are they?

Please keep us posted on your findings.

P.S. I wanted an SRT Jeep too so I made mine into an SRT clone and then hopped the engine up (see signature) to about SRT power. Best part is I now have the best of both worlds.....lower insurance rates, MDS is still active, and I get 20-23 mpg on the highway running in 4th gear.....63-68 mph. I also took an almost broken (cam/lifters and a bunch of original stuff) 06 300C SRT8 with 170K on it, off of my Grandson so he could get something more economical and not have to spend the $$$ to get the SRT fixed. You're also right, its "Mopar or No Car" for me too.
 

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Discussion Starter #4
I'm betting you swapped 6 and 8 actually.

evens are on passenger (R) side, odds on driver (L) side

2 4 6 8
1 3 5 7


Might be a bad coil, could be the connector pins on the coil have damaged ( bent) the plug contacts in the harness. Look real close in there--
Youre absolutely right i did swap 8 and 6 originally. Been fiddling with it for a couple now and ive tried several things. I swapped injectors and coils from 8 and 6 to 4 and 2 and vice versa. No change. Miss stayed on 8 and 6. Not too much mention the injectors were caked up with this tarish wax. E85 tends to create this wax but this was excessive. The car is tuned for e85.Cleaned the nozzles and everything was the same. Checked plugs for injectors and coils and theyre all working accordingly. Ive a down a compression test and all cylinders were inbetween 168 and 175 psi. Im getting o2 code for upstream heater voltage and now u is misfiring too. O2 sensor i have to change regardless but i feel its more than thst. Car is running really rich and fouling plugs. Its being flooded with fuel. I started think about vaccum leaks and too much air coming in and the computer overcompensating with fuel could be a possibility. So i start looking for vacuum leaks . i was thinking intake manifold gasket but decided look at hoses first and found that the purge valve hose that goes to the front of the intake manifold has a split crack about an inch and half long.... Thats where im at now. Ima get a purge valve fearing its stuck open due to the hose leaking and ofcourse im going to replace the hose aswell as the boot and grommet becasue theyre dry rotted and cracking. It makes sense to me . wish me luck. I also have a new pcv valve and hose air filter that I'm picking up plus the o2s. I bought a map sensor too. Im getting the multiple misfire code. O2 code and the p1128 p1129 open loop codes. Things are making a little more sense since ive found this leak.
 

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Discussion Starter #5
ileak.i
Welcome to the forum. I am guessing it's an injector problem too. Try swapping those two injectors (6 and 8) with the front two front ones on the same bank (2 and 4). See if the problem moves. You may want to try running some Techron through it (I do it about every 2000-3000 miles) and see if it cleans the injectors and gets them back to normal.

Here's a few random questions to ponder:
--How long have the new injectors been on it and why did you do away with the stock ones.....E85 or ?
--Any problem with the stock injectors or did the start after the new injectors were installed? IMO, unless you have it tuned for E85, you're probably not helping it any. Also, if you let it run REALLY rich for a long period of time you could end up damaging the cylinder walls.
--Have you done a compression and/or cylinder leak down test(s) on it?
--Any other mods. to the engine?
--Any other recent problems/history?
--Are you running the stock spark plug heat range and stock gaps?
--Any exhaust leaks on that cylinder bank?
--Any codes at all? If so what are they?

Please keep us posted on your findings.

P.S. I wanted an SRT Jeep too so I made mine into an SRT clone and then hopped the engine up (see signature) to about SRT power. Best part is I now have the best of both worlds.....lower insurance rates, MDS is still active, and I get 20-23 mpg on the highway running in 4th gear.....63-68 mph. I also took an almost broken (cam/lifters and a bunch of original stuff) 06 300C SRT8 with 170K on it, off of my Grandson so he could get something more economical and not have to spend the $$$ to get the SRT fixed. You're also right, its "Mopar or No Car" for me too.
[/
Welcome to the forum. I am guessing it's an injector problem too. Try swapping those two injectors (6 and 8) with the front two front ones on the same bank (2 and 4). See if the problem moves. You may want to try running some Techron through it (I do it about every 2000-3000 miles) and see if it cleans the injectors and gets them back to normal.

Here's a few random questions to ponder:
--How long have the new injectors been on it and why did you do away with the stock ones.....E85 or ?
--Any problem with the stock injectors or did the start after the new injectors were installed? IMO, unless you have it tuned for E85, you're probably not helping it any. Also, if you let it run REALLY rich for a long period of time you could end up damaging the cylinder walls.
--Have you done a compression and/or cylinder leak down test(s) on it?
--Any other mods. to the engine?
--Any other recent problems/history?
--Are you running the stock spark plug heat range and stock gaps?
--Any exhaust leaks on that cylinder bank?
--Any codes at all? If so what are they?

Please keep us posted on your findings.

P.S. I wanted an SRT Jeep too so I made mine into an SRT clone and then hopped the engine up (see signature) to about SRT power. Best part is I now have the best of both worlds.....lower insurance rates, MDS is still active, and I get 20-23 mpg on the highway running in 4th gear.....63-68 mph. I also took an almost broken (cam/lifters and a bunch of original stuff) 06 300C SRT8 with 170K on it, off of my Grandson so he could get something more economical and not have to spend the $$$ to get the SRT fixed. You're also right, its "Mopar or No Car" for me too.
I pretty much covered most of your questions in my reply to jtsmith. Car has long tube headers and straight piped and e85 tune. Stock otherwise. I do have a little rattle and an exhaust leak.. I am running the champion plugs with stock gap. Thanks for your reply looking forward on getting some feed back on my theories and symptoms.
 

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Discussion Starter #6
Youre absolutely right i did swap 8 and 6 originally. Been fiddling with it for a couple now and ive tried several things. I swapped injectors and coils from 8 and 6 to 4 and 2 and vice versa. No change. Miss stayed on 8 and 6. Not too much mention the injectors were caked up with this tarish wax. E85 tends to create this wax but this was excessive. The car is tuned for e85.Cleaned the nozzles and everything was the same. Checked plugs for injectors and coils and theyre all working accordingly. Ive a down a compression test and all cylinders were inbetween 168 and 175 psi. Im getting o2 code for upstream heater voltage and now u is misfiring too. O2 sensor i have to change regardless but i feel its more than thst. Car is running really rich and fouling plugs. Its being flooded with fuel. I started think about vaccum leaks and too much air coming in and the computer overcompensating with fuel could be a possibility. So i start looking for vacuum leaks . i was thinking intake manifold gasket but decided look at hoses first and found that the purge valve hose that goes to the front of the intake manifold has a split crack about an inch and half long.... Thats where im at now. Ima get a purge valve fearing its stuck open due to the hose leaking and ofcourse im going to replace the hose aswell as the boot and grommet becasue theyre dry rotted and cracking. It makes sense to me . wish me luck. I also have a new pcv valve and hose air filter that I'm picking up plus the o2s. I bought a map sensor too. Im getting the multiple misfire code. O2 code and the p1128 p1129 open loop codes. Things are making a little more sense since ive found this leak.
nptoms.numbern
I'm betting you swapped 6 and 8 actually.

evens are on passenger (R) side, odds on driver (L) side

2 4 6 8
1 3 5 7


Might be a bad coil, could be the connector pins on the coil have damaged ( bent) the plug contacts in the harness. Look real close in there--
I'm betting you swapped 6 and 8 actually.

evens are on passenger (R) side, odds on driver (L) side

2 4 6 8
1 3 5 7


Might be a bad coil, could be the connector pins on the coil have damaged ( bent) the plug contacts in the harness. Look real close in there--
Number 7 is misfiring too. Had a typo on my reply sorry
 

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I think I'd still run some injector cleaner through it. Do you have access to a good quality computerized diagnostic scanner? If so, you should be able to do a live feed on injector duty cycle and compare the good with the bad. Also, on the O2 heater circuit....if it's not heating up quick enough (or at all) you'll have a rich condition on that bank, at least if and until the sensor heats up enough to sample correctly. Why did you switch to E85 with a "fairly" stock engine? Fuel economy with E85 is normally terrible and there is usually a loss of performance unless the engine is built for it.....higher compression, forced induction, bigger cam, NOS, etc.
 
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