Engine missing after replacing intake

[efaubert1]

Ok, I should have done it myself at home, but I honestly didn't have time. Took my 02 5.4 to the local mechanic to have my coolant leaking intake replaced with the upgraded Dorman replacement intake. Gave them injector seal kits as well. Well, no it has a miss and lopes when in gear. They cannot figure it out and have had the vehicle a week today. Would you look toward the electrical system since they had to pull the alternator? Or would you look toward plugs and injectors? I have new moroso coil packs and fomoc plugs with less that 5000 miles on them, and it ran BEAUTIFULLY before I took it to them, just a leak on the coolant gasket.

My troubleshooting methodology tells me I would disconnect one injector at a time until I got to the one that had no affect and work from there. Right or wrong idea?

 

[1955moose]

If it were me, I'd run the Dtc codes, to narrow down what cylinders causing the miss. Second I'd smoke the full intake system, and see where smoke emanates from. You've probably also have an intake leak from one of the hoses. Sounds like you've got a parts changer shop. They can change broken parts, but that's it. This happens more times than you can imagine. I've been on the forum pushing 4 years and hear these bumble stories a lot. Report what they or you find.

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[efaubert1]

If it were me, I'd run the Dtc codes, to narrow down what cylinders causing the miss. Second I'd smoke the full intake system, and see where smoke emanates from. You've probably also have an intake leak from one of the hoses. Sounds like you've got a parts changer shop. They can change broken parts, but that's it. This happens more times than you can imagine. I've been on the forum pushing 4 years and hear these bumble stories a lot. Report what they or you find.

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They have tried running codes, put it on diagnostic, and get NOTHING.

 

[stamp11127]

Redneck engine diagnosis 101:

When you have a miss but no codes. Hold the throttle at the position it misses the most & wait for codes to be logged. Also smoking the intake wl show leaks as already suggested.

 

[devadip]

A compression test would be worth doing. It could be possible that something fell in the cylinder while changing the intake mainifold.

If compression is good, I would start by testing injectors to see if they are operating correctly by holding a steathscope up to them and hear that click-click that they are firing. You could also unplug them one by one to see if you can figure out if one of them is bad.

 

[Tonyray]

Check the coils and injectors to see it the wires are connected.

 

[stamp11127]

Another one post wonder...**** and he is gone

 

[1955moose]

I'm thinking they fall down that rabbit hole, and don't pop up till Easter!

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