‘02 4.6 Has me stumped

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ahow2004

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Hi guys! Just bought an 02 expy a few months ago. Had a misfire in cylinders 1 and 7 according to Obd2 scanner, got around to changing plugs and coil packs this weekend, along with cleaning throttle body as i saw online in videos. Also had 02 sensor codes, planning on working on those some other time.

Almost immediately after i restarted the vehicle had issues with high idle and stalling out when i put it in drive, or sometimes within seconds of starting up. MAF sensor code popped up p0102 so i took apart my intake and reassembled it. Code disappeared without using any maf cleaner. Drove around a bit and idling and stalling issue returned with p0171 and p0174 codes this time. Repeated process of double checking my work on my intake. Codes disappeared once again but acceleration still felt funky and hesitant and still noticing some weird idle rpm patterns. Saw online to do a throttle body relearn, which helped a bit but not noticeably. Car hasnt stalled since but i havent attempted to drive it much. The inconsistency in the codes is whats worrying me.

I do know my throttle body gasket was cracked and i will need to replace it. It was so damaged i was unable to reinstall it. Could that be the source of my issues? Or will i need to check for a vaccum leak? Or is it the 02 sensors ive been ignoring?

Any pointers in the right direction are appreciated.

Ive got an amazon cart with a replacement gasket, IAC, and MAF ready to go.
 
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ahow2004

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Update. P0102 returned rhis morning after a bit of driving around. Car also stalled out while sitting in idle and after returning to park from drive.
 

jr1under

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Just a shot in the dark...you said you had misfires on #1 & #7 and changed the plugs and coils. Did you replace all eight or just the two that were misfiring? If all eight, then I have no further questions.
 
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ahow2004

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I changed out #1 and #2 on passenger side and all except #8 on drivers side. So there are three plugs and coils in there I didn't change due to lack of time and me getting frustrated lol.
 

jr1under

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Further questions. Did you see any P030x codes? Are all four COP's on each bank the same brand/part #? My learned-the-hard-way experience is that mismatches can lead to misfires on both the old and new ones in the same bank. And they're more expensive but I would use only Motorcraft coils.
 

pitdexion

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You have a large vacuum leak. While idling, spray brake cleaner around after maf and listen for rpms to increase. There is your vacuum leak. Said gasket missing will cause this problem.
 

JamaicaJoe

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I changed out #1 and #2 on passenger side and all except #8 on drivers side. So there are three plugs and coils in there I didn't change due to lack of time and me getting frustrated lol.
Did you get your sorted out? I opened a thread on mine stumbling. But getting no codes.
 
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