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Has compression and doesn't leak down gets spark and fuel pulled codes on it said cylinder 3 miss and said rich/lean car doesn't have much get up and go bought the car hoping it didn't need much im thinking it has a stuck valve or something in that neighborhood car has 197k miles any help would be great
 

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Has compression and doesn't leak down gets spark and fuel pulled codes on it said cylinder 3 miss and said rich/lean car doesn't have much get up and go bought the car hoping it didn't need much im thinking it has a stuck valve or something in that neighborhood car has 197k miles any help would be great
So you ran a compression and leak down on it and both came out good. What comp? Mine is around... 160s after new MLS head gasket and hand lapping the valves. All 4 cylinders are pretty close. Maybe within 5 - 7 lbs of each other. I crank around 4-5 times on each cylinder for max compression read on the gauge. If you have good comp and very little leak down likely not a sticky valve...though with that mileage anything is possible. FYI That motor does like to build up carbon deposits on the back side of the valves (intake and exhaust). Also the oil drain back holes in the pistons behind the rings were so carboned up on mine so badly I had to drill em clear with a dremel and micro bit! If you wanna clean the inside a bit and lube the upper end, you could run some seafom motor treatment and use per instructions on the can. Then change the oil and filter.

For my $$$ with a single cylinder miss, I'd suspect plug, plug wire, or coil issue. Cheap enough to change all 3 (Rock auto) especially since you don't know the last time those were done. I've run ngk copper and platinums. Cant really say i've noticed much difference with either.
 

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So you ran a compression and leak down on it and both came out good. What comp? Mine is around... 160s after new MLS head gasket and hand lapping the valves. All 4 cylinders are pretty close. Maybe within 5 - 7 lbs of each other. I crank around 4-5 times on each cylinder for max compression read on the gauge. If you have good comp and very little leak down likely not a sticky valve...though with that mileage anything is possible. FYI That motor does like to build up carbon deposits on the back side of the valves (intake and exhaust). Also the oil drain back holes in the pistons behind the rings were so carboned up on mine so badly I had to drill em clear with a dremel and micro bit! If you wanna clean the inside a bit and lube the upper end, you could run some seafom motor treatment and use per instructions on the can. Then change the oil and filter.

For my $$$ with a single cylinder miss, I'd suspect plug, plug wire, or coil issue. Cheap enough to change all 3 (Rock auto) especially since you don't know the last time those were done. I've run ngk copper and platinums. Cant really say i've noticed much difference with either.
Had around 155-165 a cross the board coil pack fires every cylinder all plugs and wires are new I've ran 4 bottles of seafoam through it no luck on that I have a pretty noisy lifter on cylinder 3 sounds like on the intake side starting to think its an intake valve not opening all the way up and making it miss I had the fuel pressure checked it was good is it possible for a lifter to get stuck and it make it miss this bad idk I've never seen one miss from a bad lifter but it sure beats pulling the whole head to see if a valve is cracked or not seating perfectly car doesn't use oil leak oil im not losing any coolant there's no water in the oil or oil in the coolant im lost at what it could be I've been working on cars my whole life I've never seen something have good compression and have a valve issue or head gasket issue the injectors are working I pulled them and had them flow tested im about ready to pull the whole motor k series swap it lol seems like it would be cheaper
 

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Had around 155-165 a cross the board coil pack fires every cylinder all plugs and wires are new I've ran 4 bottles of seafoam through it no luck on that I have a pretty noisy lifter on cylinder 3 sounds like on the intake side starting to think its an intake valve not opening all the way up and making it miss I had the fuel pressure checked it was good is it possible for a lifter to get stuck and it make it miss this bad idk I've never seen one miss from a bad lifter but it sure beats pulling the whole head to see if a valve is cracked or not seating perfectly car doesn't use oil leak oil im not losing any coolant there's no water in the oil or oil in the coolant im lost at what it could be I've been working on cars my whole life I've never seen something have good compression and have a valve issue or head gasket issue the injectors are working I pulled them and had them flow tested im about ready to pull the whole motor k series swap it lol seems like it would be cheaper
Sounds like you've covered the basics. Id say a cracked valve/ bent stem or damaged seat are all unlikely as those would result in lower comp on that cyl. and would definitely show up in a leakdown test. Injectors were flow tested but what about a possible wiring issue with injector wiring or injector driver in the PCM? Not sure if OBD2 provides those codes but likely does.
 

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Sounds like you've covered the basics. Id say a cracked valve/ bent stem or damaged seat are all unlikely as those would result in lower comp on that cyl. and would definitely show up in a leakdown test. Injectors were flow tested but what about a possible wiring issue with injector wiring or injector driver in the PCM? Not sure if OBD2 provides those codes but likely does.
A bad lifter could definitely be noisy. As for a collapsed lifter that wont pump up...youd have low or no compression on that cylinder bcus the valve wouldnt open or not as much as it should. An exhaust valve that doesnt open all the way would likely result in dilution of the intake charge due to residual exhaust remaining in the cylinder...and also likely reversion which may show as sooting on that plug. A stuck lifter that won't compress at all may result in the valve hanging open.

I'd think the seafom would've unstuck any stuck lifters. A broken one is unlikely but I wouldn't rule it out. A broken valve spring is also unlikely for a stock car that hasn't seen insane rpm. It would likely be very noisy too. I suppose anything is possible.

I'd look for injector codes next if you havent already (which could indicate wiring or PCM issues). If none then a visual inspection inside the valve cover is in order. Inspect everything the best you can.

If you suspect lifters and want to replace cylinder 3 lifters It is possible to remove and reinstall rocker arms with the cams still in place tho I've never done it. This may help. DIY Lash Adjuster (Lifter) Removal Tool
 
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