Urgent advice needed on rough running/misfire! (1 Viewer)

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Oct 30, 2016
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NY
1998 with 330k on it. The truck had been running beautifully but last week it started to need long cranks in order to start and sometimes multiple tries but only after it warmed up, cold starts were no issue. After searching I suspected it was the coolant temp sensor so I snagged on from advance and put it in today. The sensor itself was broken and was held together with zip ties so I figured it was the issue. The whole thing crumbled as I took it out. With the new one in it fired right up but as the car started to warm up I started to have a misfire that increased as I drove. I had a CEL flash a few times. I thought maybe I had knocked an ignition coil connector loose when I put the airbox back on but upon further inspection everything was where it should be. I pressed everything down just to be sure and I still had the misfire. Here is where I am stumped. The spark plugs, ignition coils and starter are all new in the last 15k and it was running beautifully before I replaced the coolant sensor. Is it likely that I got a faulty sensor or is something else happening? This could not have happened at a worse time as I am moving this saturday from NY to MN and had planned to tow a uhaul trailer with all of my belongings. I really need some help so that I can get this things running again so I can get to my destination. All input is greatly appreciated!
 
Have you been able to read the CEL codes at all? That may give you an indication what cylinder is misbehaving, or if the issue is related to something else. If all the coil packs are new and guaranteed OEM (lots of counterfeit eBay junk out there) then...

Changing the fuel filter should be the next step, especially at that mileage. It’s super easy, right behind the battery. Next, I’d say consider changing the fuel pump.
 
Haven't been able to pull the codes because all of the auto part stores are a decent distance and I can't drive it in the condition its in.
 
Is flashing cel an indicator of cylinder misfire with the number of flashes indicating a particular cylinder on 100’s?
 
Is flashing cel an indicator of cylinder misfire with the number of flashes indicating a particular cylinder on 100’s?

No, a flashing CEL is an indication that the misfire is dumping enough unburned fuel into the exhaust to damage the cats.
 
Ignition coil. But yes get a reader. The ancel one on amazon works well.
 
Ignition coil. But yes get a reader. The ancel one on amazon works well.

He said all were new?
But yes, buy a code reader. Worth their weight and it doesn’t have to be a super expensive one. Be aware that most the bluetooth ones on amazon don’t work with iphones.
 
Walking to Walmart might be faster for the code reader. Should be $20-30 for a basic unit.
 
You said the spark plugs and coils are relatively new. Are they OEM/Denso, or aftermarket junk? I’ve seen plenty of cheap aftermarket coils and plugs fail in less than 10k miles on multiple Toyota engines...
 
He said all were new?
But yes, buy a code reader. Worth their weight and it doesn’t have to be a super expensive one. Be aware that most the bluetooth ones on amazon don’t work with iphones.

Odds are that one of the new ones took a dump. That being said we need codes to help diagnose. Could be plenty of other things.
 
Remember there are fake DENSO sold on eBay and Amazon. I get OEM used Sequoia/tundra 2uzfe coils from the yard. Those work great! My 97 4runner still got OEM coils.
 
Coils were aftermarket junk apparently. Cylinder 6 misfire so I snagged a new coil and it is back to normal. So far with the new coolant temp sensor and coil it fires right up even when warm. Fingers crossed this fixes it! Thanks everyone for their input.
 
Coils were aftermarket junk apparently. Cylinder 6 misfire so I snagged a new coil and it is back to normal. So far with the new coolant temp sensor and coil it fires right up even when warm. Fingers crossed this fixes it! Thanks everyone for their input.
Better go ahead and buy 7 more (*OEM*), because the rest ain’t too far behind from failing too...
 
Aaaaaaand the trouble starting is back....Back to square one I guess.
 
Going through the same thing with my 00 with 220k. Had rough idle at a stoplight while in D with foot on the brake and was running rough every now and then. Pulled and inspected all coils and plugs and replaced plugs. Coils looked old and most had a crack running the entire length. A couple days later cylinder 3,4,6 had misfires (assuming pulling them accelerated failure). Replaced the 3 and ran better for a couple days then started running rough again. Ordered the other 5 and will be replacing tonight. Hope it clears it up. Denso of course! Has a new starter, alternator and battery so this should do the trick. PCV is next if not.
 

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