Extensive Tune Up Misfires

[jamesdking]

Here’s a big clue. All 104 misses on 5 came in a rush. I’m pretty sure it was the on-ramp or a wot I did on the freeway. I’ll try again after work tonight and pay closer attention. But I’m pretty sure #5 is a big problem. I’ll swap in a new wire and perform a compression test ASAP

 

[jamesdking]

#5&1 both read 130 psi dry. Didn’t have much free time today. I’m pressed and got what I could done before work. I’ll do all of them later with all the plugs out. Just wanted to look for a completely dead cylinder.

fuel filter changed again. Gauge still reads 51 at idle and koeo maybe a tiny bit higher. Closer to 60 once I turn it off and it holds for at least 20 min. No black crud in it this time.

new wire on #5 and isolated it from the others

Dumped a bottle of Marvel snake oil in the crank case. I’ll change the oil in two days.

Seafoam in the break booster line and gas tank. Smoked some but I’ve seen way worse.

I’ll run a scan on the highway in an hour commuting to work.

 

[Schurkey]

130 psi isn't bad, depending on the accuracy of your gauge and the altitude you're at.

Around here, I hate seeing less than 145-ish; and I'd really prefer 180 but nothing older reads that high. But I've seen cylinders run (above idle) with 50 psi, and run at idle with 80. Yeah, the engines were lazy.

 

[jamesdking]

Still missing on 5. It was after getting on it at 75 mph and letting off the gas abruptly.

 

[Schurkey]

Doesn't misfire when you have your foot on the pedal accelerating, but misfires when you coast???

Still won't go over 2000 rpm?

 

[jamesdking]

Doesn't misfire when you have your foot on the pedal accelerating, but misfires when you coast???

Still won't go over 2000 rpm?

It didn’t log the misses until I was coasting. Could that be my cheap iPhone app scanner delaying? I suppose. But it was when I let off the gas completely to slow back down to the speed limit. Floored on the ramp had zero misses and it revs up as normal over 2000rpm. I haven’t had the opportunity to take it over the mountain pass yet to replicate the flashing CEL yet and see if it still lags at 2000 rpm. Also the two logs I ran yesterday and tonight had no accompaniment of a CEL flashing or otherwise.

 

[delta_p]

I would try cleaning the mass airflow. if it's dirty, loaded throttle is going to put a lot of air in there without fuel. I would also try pulling the plug on the mass airflow meter and try hitting the on ramp when it's run in open loop.

 

[jamesdking]

I would try cleaning the mass airflow. if it's dirty, loaded throttle is going to put a lot of air in there without fuel. I would also try pulling the plug on the mass airflow meter and try hitting the on ramp when it's run in open loop.

I’ll give it a try. But why is it only #5??? The logic part of me is dying to understand this.

 

[GoToGuy]

Do you have the free factory service and repair manuals available here to download? Everything has a proper name, it's how we all know what your talking about or describing to tge forum. Pretend were all deaf and blind get it? Get the manuals it will make your life easier or keep guessing and changing new parts and eventually your problem will be fixed. Good luck.

 

[jamesdking]

Do you have the free factory service and repair manuals available here to download? Everything has a proper name, it's how we all know what your talking about or describing to tge forum. Pretend were all deaf and blind get it? Get the manuals it will make your life easier or keep guessing and changing new parts and eventually your problem will be fixed. Good luck.

Clearly I don’t man…. I came here to a group of like minded enthusiasts to ask questions and learn. I felt like up until now that I had been apologetic of my misspoke terminologies and had corrected them. I really did try to follow the most basic schematic of steps to fix what seemed to be a simple tuneup needing done to an older truck. Once that was exhausted I reached out to you guys and gals. Your comment discourages me and your typos amuse me. Thanks for the advice tho. I’ll go find the manuals you mentioned but didn’t reference.