miss firing

[mille1cw]

Ok. I'm throwing codes for a #1 & #3 cylinder misfire. Here's the driving diagnosis. Rough "off balance feel" idle, crusing speed rough shaking, accelerarion/ WOT not an issue at all; feels lkje normal. Any takers?? I was thinking plugs or injectors respectively...thanks for your continued support!

 

[FordandPolaris]

Well I lean towards plugs before injectors. Since cylinder 1 is right up front (passenger side), pull the plug and see what it looks like. If it is really gapped out (more than .056) I would say you have found the problem. Repeat with cylinder 3.

I did the dance with misfires on 3 cylinders. One would die completely and throw the code, so I would replace just that plug and COP. Did that over a year's span. Finally just replaced the entire set with new plugs and COP's and it was well worth it.

 

[mille1cw]

Do you think it might be the Throttle Position Sensor? I had a heli-coil done to all cylinders within the past 6 months, all plugs and practically new. Thanks

 

[stamp11127]

Use some logic here, how is the tps tied to just the #1 & #3 cylinders?

Move one cop and see it the problem moves with it.

 

[FordandPolaris]

Use some logic here, how is the tps tied to just the #1 & #3 cylinders?

Move one cop and see it the problem moves with it.

Agreed, if the plugs are newish but the COP's are original, they are the next link in the chain. TPS is more than likely not it. Like Stamp said, swap it to a different cylinder and see if that one receives the misfire.

 

[1997SCEBFEX]

agree on not being TPS.

work on the cel(s) that you have. if you ohm out the cops, you'll more-than-likely find suspects.

PanHandler.

 

[keithnra]

mostlikely cop

 

[mille1cw]

That would be the most logical explanation, i agree now after i've said it. I replaced the COP but the issue still persists. I tried to replace the plug but it was giving me some tension and i was weary of putting too much torque on it seeing as it has been hell-coiled* and didn't want to strip the insert. I pulled the fuel rail and the #3 injector to see if it was plugged, no dice but cleaned it anyway. I understand sticking to the issues of that cylinder so could it be the fuel injector? Thx

 

[stamp11127]

There are a bunch of "could be's". Check the plug.

 

[FordandPolaris]

Like Stamp said, you are going to have to remove that plug. If that insert is strong enough to hold the plug from flying out under high pressure, it is probably not coming out if you take out the plug. But you do also have to prepare for such an event. Maybe check with local part shops to see if they loan the tool needed to reinstall a heli-coil.

 

[metaldrgn]

If it's working fine at WOT it could be something with the egr system.

 

[Snapshot]

I'm not sure if you've got this fixed yet, but I had a similar issue with the misfire. One of the best things you can do is swap out the coils to see if they're bad. For example, remove coils #1 and #2 and swap them. Plug them up and start the vehicle. Once the vehicle is running, remove the wire connector that goes into coil 2. If you notice no change in the sound of the engine, then you have a bad coil pack. If nothing happens, then pull the wires out of coil 1. If nothing changes then you have a bad spark plug. I hope this makes enough sense for you do. Turns out for me, I had a bad coil pack on cylinder 6.

 

[Go4Life]

Yeah I'm thinking COP's too. I recently changed mine and it was doing the same thing you're describing "mille1cw". My dad bought the 1997 Expy back in 2006 and I when I got it I changed the COP's and noticed that they were the original ones from the factory. They were in bad shape.

 

[mille1cw]

Took it to my local guy and he did a leak down test on the engine, either bent or burnt valve, either a $2,000 valve job, or a new engine. pretty pissed but looking to sell if anyone wants this truck for real cheap? PM me if you're interested.

 

[Snapshot]

I'd get a second opinion on that. If you had a bent valve, I don't believe your vehicle would even start. There's a old trick to seeing if you have a burnt valve, you can stick your hand on the exhaust and if it sucks your hand in then you might have a burnt valve. I would definitely try the swapping coils to see if you can pinpoint two bad coil packs.

 

[metaldrgn]

would be way cheaper if you pulled the head