Misfire no cel very frustrating.... please help

07GtS197

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Something dead wrong.

What he said. The car should start and idle with the maf unplugged. Theres something bigger going on. Youve eliminated spark and fuel so it has to be something with air or a sensor that doesnt pertain to the issue. It does sound like a vacuum leak though as youre pcv system only works at idle.
 
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thatone1320copcar

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Already swapped in ford pi manifold. That helped ever so slightly. Cleaned maf, that helped out alot. Its still the same issues but cleaning the maf did help. Now of i take it for a drive and floor it it dramastically smooths out when the rpms get over 3k
 

1994Gtvert

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Checked dipstick. Oil smells strongly of gas

if you have gas in your oil...that leads me too believe your having leak-down issues from a injector(s). Basically it means your injector(s) are letting fuel pool up in a cylinder, and it's bleeding down the walls. But it still doesn't explain the misfire fully, but would cause some issues. Have you done a compression test on the cylinders? Then you can eliminate bad rings or damaged cylinder walls. Also you stated a lean condition, was it the plug in 1, 2, and 6? If just in 1, 2 it could be a blown head gasket or its starting to fail. Don't take any of this as hard facts, just trying too lead you too a fix.
 

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I have had all kinds of small issues that caused problems like this. Once I discovered the silicon intake boot had slipped off of the TB and it would seal ok/well enough until I tapped the gas and then when the engine moved it caused problems. Another time I noticed a miss and got under the hood and notices one of my spark plug wires was wiggling a little more then the others because it had popped off the plug. Slapped it on and took off and it was fine for about an hour and then I had the same problem, same plug wire. When it got hot enough it would pop off and ended up replaced. Start simple and get a little rough with your wiring. If everything is mounted correctly you would be able to wiggle and slightly pull on the wiring and have no issues but its really easy for a wire connection to get a little loose when the engine warms it up.
 
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thatone1320copcar

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Just found out something... my odometer hasnt moved since i bought the car. So real milage is unknown. Decided to replace upstream o2 sensors so i know they are good and instead of having an oem sensor on one side and a newer sensor on the other i will now have two new ones on there. Even if they arent the problem i know i wont have to replace them for a while. Not sure how to get passenger side sensor off though as it looks to be touching the frame and theres no space to get a wrench in there.
 

07GtS197

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I only swapped o2 sensors in an sn95 once when swapping mid pipes but while under the car it looks doable. Other than swapping the sensors look for anything else disconnected, theres an underlying cause of all your issues. Maybe check the tps.

Your odometer gears are brittle pieces of plastic. They commonly break causing both to not work. Theyre cheap on ebay.
 
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thatone1320copcar

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So after toying with the car some more, found out my compression tester is bad.... and also unplugged o2s and maf and it ran like that better than before. I started playing with the injector clips on the dead cylinders and it changed the idle to i cut the old clips off and got new pigtails from autozone and installed them, no difference. But on what looked to be the main harness there is what apears to be a section where the insulation is burnt off the wores and that may be the cause? Not completely sure.
 

07GtS197

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If it runs better with the maf and o2 sensors unplugged then your problem lies with those items. The car will run with things unplugged (for instance, the maf) and the ecu will use other sensors to keep the car running. That being said, if it runs like crap with something plugged in and better with it unplugged then the sensor is sending messed up info to the ecu. You can test the maf before moving forward but not the o2 sensors. You can datalog before doing anything to check sensor outputs.
 
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thatone1320copcar

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Sensor outputs on o2s were bank 1 sensor 1 0.2v bank 1 sensor 2 1.4v bank 2 sensor 1 0.6v bank 2 sensor 2 was 1.4v. Now cold start yesterday i had some fuel scented smoke on startup. Mostly from the passenger side hardly any on driverside, wondering if a pluged cat is my issue....
 

07GtS197

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Did the voltage fluctuate when in closed loop? Running rich when starting (open loop) is normal. You could have a messed up cat, a vacuum gauge hooked up to a vacuum source will confirm a plugged cat. You can use a vacuum gauge to diagnose a lot of things on cars. Its one good tool to have. Did you datalog any other parameters?
 
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thatone1320copcar

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Voltage was fluctuating massivly. And i do have a vacuum guage but ive never needed to use it. It was my grandfathers but i never encountered a time to use it. Nows my chance??? Lol but on a side note i planned on dropping the exhaust tomorrow when i replace my starter and pass side o2 as its not engaging the flywheel sometimes when i go to start it. Figured id start it without the exhaust hooked up see if theres a change
 

07GtS197

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Thats probably contributing to your problem then. They shouldnt fluctuate massively but they should steadily switch. Fluctuating means theyre trying to correct afr because its off constantly. Today is a great day to break out that tool! Lol, its old school. It was important years ago in detecting problems with engines before they became electronically controlled. And they can diagnose a myriad of issues, even plugged exhaust.

Are you going to run it with your exhaust disconnected at the manifold to mid pipe or mid pipe to cat back section? Neither of them will really help rule out the cats.
 
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thatone1320copcar

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Wait o2 wernt really fluctuating. Car voltage was. And i was gonna run it right before the cats at the manifold
 
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thatone1320copcar

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Had someone else look at the results from the vacuum guage and they said to check inlet and outlet temps of cats.... well the inlet of the tiny precats was around 350-400.... outlet was showing 120 degrees.....
 

07GtS197

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You can try tapping on your cats with a hammer (dont get too crazy lol) to unclog them. Otherwise its time for new cats.

Im still curious about your battery voltage and o2 sensor outputs. The o2 sensors should be constantly correcting afr even at idle so you will see variation of the voltage (called switching) but not too erratic. Now the battery voltage shouldnt be all over the place, thats another thing to look at. Was the idle steady when battery voltage was all over the place? When you can, have someone hold the gas open to 2500 rpms when you measure alternator output (or across the battery terminals) it sould be holding steady. If not its most likely the voltage regulator.
 

ksustang

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Have you had the alternator tested and is the battery fully charged. A bad or going out alternator can cause a lot of issues.
 
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thatone1320copcar

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New alternator about 4 months old. I think the battery voltage was going crazy because the idle was too
 

96blak54

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Where is your location? Maybe a forum patron can hook up with you. Help you out. I know I would!
 

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