Hard Start in 96 454. Please Help, this is a doozy

[brycebba]

The problem is definitely getting worse though. Cruising down the freeway at steady throttle was fine before a week ago and now it was shuttering at even the slightest throttle change

- Bryce -

 

[98_k1500]

Just keep running the piss out of it. When it quits all together, the problem will come more apparent.

 

[brycebba]

Isn't there a possibility that I could damage something though?

- Bryce -

 

[98_k1500]

I was kidding lol. If it is getting worse, it needs to be addressed. I wish i could do more to help diagnose your problem. Never really fooled with a EFI big block.

 

[brycebba]

Haha I figured but with some people you never know. I am stumped too

- Bryce -

 

[brycebba]

In case this helps in regards to the o2 sensor questions I took some video of the data logging which includes MAF rate, engine RPM, Bank 2 Sensor 1 O2, and Bank 1 Sensor 1 O2. You will have to excuse my son, he was holding onto my arm so when I would tap the throttle he would pull on my arm and cause the camera to shake.

http://youtu.be/8ZLERDIoLDg

 

[JollyGreen]

If it was me, before I threw any more parts at it, I'd pull the upper intake off and take a look at that distributor gear. I'd bet my bottom dollar that gear is worn. I know that the hard start WILL get worse as the engine heats up with a worn gear. You've replaced almost everything fuel related, so IMO that leaves the distributor and cam / crank position sensors. If it's misfiring going down the road at highway speeds, you could have the distributor issue and not have any codes (p1345)....yet.

 

[brycebba]

I have never pulled a distributor before, is it something that someone more experienced should do? Would the unit wiggle at all if the gear was worn?

- Bryce -

 

[brycebba]

Well this is just ridiculous. In Utah its been pretty warm but yesterday we had a crazy low temperature for this time of year and I woke up to a 40 degree morning. The truck idled still kind of weird, little stumbles here and there but there was hardly any noticeable stumbling when going. The truck was almost running perfect. Im going to pull a plug this morning to see how it looks because Im betting it has tanned up at least a bit. I must mention, even once the engine was completely warmed up it was still running the same so it seems that low ambient temperature does help the situation despite engine temps.

Here is a clip of full throttle which it couldnt do 2 days ago when it was warm. I even stabbed the throttle a few times from a dead stop and it didnt stumble at all. I even put extra load on it going about 45 and applying lots of brakes and more throttle without letting it downshift and it ran great through it. What is going on!!!???

http://youtu.be/KZ4UKjtTgg4

 

[woody31]

if the timing gear ,,looks ok,,i will throw this at ya....timing chain slop,,will cause all the symptoms you describe,,factory sets are horrible compared to a cloyes or equal quality set,,good luck..