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Discussion Starter #21
I have had a bad IAC valve that caused a very rough idle when cold started. It caused misfire codes. At operating temp it ran fine. A dirty injector can cause out of range fuel trims. I run a bottle of Chevron Techron once in awhile. It has cleaned up the injectors, giving better trim values and stopped misfire codes. Moving #4 injector to a different bank to see if the code follows can give a clue about the misfire. What injectors did you purchase, brand new from Denso?
Yes denso oem green
 

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Discussion Starter #22
sounds like a shotgun repair.

You're going through fuel like crazy? Then it's running rich. need fuel trims and I can tell you more. What average range are you seeing, or what high and low are you seeing from b1s1 and b2s1 long and short? It sounds more like there isn't enough air at idle. The throttle pedal is an air control valve, not a gas pedal. it gives no extra gas.
These are averages i think
 

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What elevation do you live at? The big differences in B1 and B2 are only slightly concerning. If I had to guess, I’d think cylinders 3 and 4 are either getting too much fuel (injectors stuck open or dirty, fouled plugs, bad coils) or not enough air (plugged/ broken interior of manifold, debris, worn camshaft, low compression)
 

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Discussion Starter #24
What elevation do you live at? The big differences in B1 and B2 are only slightly concerning. If I had to guess, I’d think cylinders 3 and 4 are either getting too much fuel (injectors stuck open or dirty, fouled plugs, bad coils) or not enough air (plugged/ broken interior of manifold, debris, worn camshaft, low compression)
I live at about 90 ft houston tx,,, 3+4 are listed as misfire...+ random.... new plugs and injectors oem on both. Ordered 2 coils oem and a new iacv oem
Thanks for help
What elevation do you live at? The big differences in B1 and B2 are only slightly concerning. If I had to guess, I’d think cylinders 3 and 4 are either getting too much fuel (injectors stuck open or dirty, fouled plugs, bad coils) or not enough air (plugged/ broken interior of manifold, debris, worn camshaft, low compression)
just fixed rid nock,,,, bottom cam great just had heads done all good there.... with head new plugs 4 months.... so i guess it leaves coils or iavc which ive ordered oem
 

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Move the coils on 3 and 4 to 1 and 2. Of the misfire stays at 3 and 4, it isn’t your coils.
 

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Discussion Starter #26
Move the coils on 3 and 4 to 1 and 2. Of the misfire stays at 3 and 4, it isn’t your coils.
took iac of of circuit and car reacted poorly, missing became worse. Is there a way to to check iac, and voltage coming to it? Looked at wires and harness look good but the signal comes from ?ecu? Any switches or relays i should check?

Drove today symptoms in car, when slowing clutching car goes to 500 rpm ? first line on dial. Normal. but it wants to die with misfire.....after a bit more driving....the next time it only backed down to a thousand and wasn't dying and misfire was present...then third time went to 500 again and died, restarted without an issue.....overall drives but missing.

gonna check compression tomorrow, I will move coils also and pass it on.....

thnx for your help
 

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Discussion Starter #27
took iac of of circuit and car reacted poorly, missing became worse. Is there a way to to check iac, and voltage coming to it? Looked at wires and harness look good but the signal comes from ?ecu? Any switches or relays i should check?

Drove today symptoms in car, when slowing clutching car goes to 500 rpm ? first line on dial. Normal. but it wants to die with misfire.....after a bit more driving....the next time it only backed down to a thousand and wasn't dying and misfire was present...then third time went to 500 again and died, restarted without an issue.....overall drives but missing.

gonna check compression tomorrow, I will move coils also and pass it on.....

thnx for your help
Sorry family issues have to take a few days before ill update
 

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Discussion Starter #28
Ok fellas this is where im at..still misfire, cycles normal then sputters when idling. Do to storm coils and iac has not arrived so i fid some things on my own. Yesterday sat i looked everywhere i could reach with brake cleaner looking for vacuum leak. Could not find one but car ran without coding for a 20 mile drive. However this morning sun i knew when i went to it that it had returned and sure enough. So today tried majic brake cleaner but nothing good came of it. So i decided to take throttle body off and inspect aic and tps. Tps ohmed with rotation of dial full open throttle position to zero from maybe 9 ohmes at idle position. the iac is denso so i guess i did right in the past, i connected it to 12 volts and it did spin so i think this is good news. Drove it couple times around the block runs great no lack of power very sensitive as always but buring a lot of fuel in just maybe 3 miles 1/8 of tank. Her are fuel trims and codes before working no tps and no oil control issues after there on the report. Not sure why.
80978
80979
80980


so the above were before pulling throttle body and below are what came up after
80981
80982



so the car cycles still between 1k rpm and 500 rpms at idle at 500 it runs very rough and wants to die. At speed hardly noticeable but burning fuel.
thanx for any help you may give me im running out of ideas.
 

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Discussion Starter #29
Note per turbo jimbo i did move the coils 3&4 to 1&2 position before driving it on sat
 

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Sort out the P0120 and P1656 and I'll bet the problem goes away.
 

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Compression 175 in 2 3 4 90 in 1
gonna use camera to look into cyls to see if damaged maybe try to re ring it from the top misfire right now still says p0304 still variable sometimes misfires other times not so sure coded then no code...when i did rod nock i didnt notice damage but view is limited.....ithink head can be pulled from top after camera viewshows no damage to cyls sometimes burning fuel and others not....this is the strangest issue how can a mechanical issue be intermittent...any thoughts?
 

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Compression 175 in 2 3 4 90 in 1
gonna use camera to look into cyls to see if damaged maybe try to re ring it from the top misfire right now still says p0304 still variable sometimes misfires other times not so sure coded then no code...when i did rod nock i didnt notice damage but view is limited.....ithink head can be pulled from top after camera viewshows no damage to cyls sometimes burning fuel and others not....this is the strangest issue how can a mechanical issue be intermittent...any thoughts?
One cause for low compression is valve lash out of spec. Worth checking.
 

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Discussion Starter #35
Not sure if this is issue just had head rebuilt 3000 miles ago
any thought
 

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Compression 175 in 2 3 4 90 in 1
... sometimes burning fuel and others not....this is the strangest issue how can a mechanical issue be intermittent...any thoughts?
I wouldn't call this intermittent. I don't think that your engine ever runs right. Whether or not the bad cylinder fires is situational. The low compression could be the reason why the cylinder doesn't fire at idle, and with the throttle open it may have enough pressure to ignite.

If the problem really is zero valve clearance, then the compression could depend on engine temperature as parts expand thermally.
 
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