I own a 2000 f150, 7700 with 199,000 miles, 5.4 eng. In drive with foot on brake, it idles at 600 rps, fairly smooth. When I accellerate from a stop the engine shudders. Ten months ago I had the plugs replaced, last week I bought 8 new coils on ebay for about $75.00 and I installed them, no change. I removed the down stream o2 sensor from the exaust, it was as clean as blued gun metal. Can these 2 sensors be cleaned or tested?
The service engine lite is not on.
Can someone give me list of things to check?
thanks nick c

 

You need to check your MISFIRE PIDs with a scan tool in Mode 6.

 

I went to auto zone, no codes present, I put in a small bottle of Lucas injector cleaner. I have a total of 4 o2 sensors in my exaust, can they be tested with an ohm meter?
I found the MAF sensor and one other sensor in my air intake and sprayed them with throttle body cleaner and compressed air, can they be tested?
The EGR valve itself may be ok, I put a piece of vac line hose and sucked, it held a vacuum and I could hear the diaphram move when I let go the vac. At idle there is little or vac from the hose going to the EGR valve, instead it feels like a vibration. I have a vac gauge, what should it read? This vac line goes to a small black,round box what the name of it and what does it do?
thanks nick c

 

Unfortunately just because one gets new components, like your 8 new COPs. Does not automatically mean they are good out of the box. Cheep aftermarket COPS tend to have a high failure rate....yes right out of the box or in your case a few months down the road.

Hopefully that you used motorcraft plugs and torqued them to 28ft/lbs. dry, no anti seize

Typically...the shudder or vibration you're experiencing is a low grade missfire ...NO codes are tripped and can be hard to track down.

the Mode 6 level of scan that projectSHO89 is referring to, generally is only available at dealerships or very well equipt service garages. If I understand correctly, This allows the technician to monitor the intensity and timing of each spark cycle for each cylinder.

your vacuum pressure should be near 20in of pressure...anything below 17 or 18 indicates mechanical issues of some kind....bad rings or bad valves, etc.

You can remove the throttle body housing and give it a thorough cleaning. There are 2 EGR ports in there that tend to get clogged up and can give rough running conditions. Plus cleaning the back side of the throttle plate can be helpful too.

BTW... one should clean the MAF sensor only with cleaner that states it is safe for MAF sensors. That little filament in the MAF sensor is pretty sensitive and need to be only air dried

 

9 times out of 10,, its the COPS -- one bad one, need a code.

 

The down stream HO2 sensors do not have any effect on how the vehicle runs. They are only there to monitor the efficency of the cats.

And there really is no need for you to try and 'test' any of the HO2 sensors. The PCM does this periodically, checking for the minimum and maximum allowable voltages as well as the time in milliseconds for the HO2 sensors to switch from rich to lean and lean to rich. If an HO2 sensor fails any of the PCM controlled tests a specific DTC will be set.

 

I can read Mode 6 data with a $20 ebay BT adapter, a $5 app, and my Android smartphone.

This ain't rocket science, it's computer science.

 

cop may be good as well as the plugs... but the boots that concect them(like the old plug wires) if they re not tight or sealed; yep you guessed it shudder at accelleration let us know what you find out..

 

Are you sure its the engine? anything not acting right would be picked up by the OBD computer. It could be your torque converter or U joints sticking. Since nothing on these trucks can be lubed from the outside that can be a possibility.

Also, O2 sensors DO have an affect on the way the engine runs because they monitor exhaust gasses and tell the computer to adjust air/fuel ratio depending on their reading. If you had ANY bad sensors OBD would pick it up.

My truck does the shudder, it seems like an engine shudder but its more likely the u joints or transmission. Even the rear end can cause this kind of shudder if it is a limited slip and hasnt had a fluid change in a while. Pick something small and work from there. Start eliminating things and eventually you will find the answer. IF you cant live with it....

 

If some of you had researched the issue, you would have seen it as a faulty coil.
The coil developes shorted turns but still functions in a limited capacity.
It won't set a code because it's not a 'hard' fault as it comes and goes causing the cancellation of the record that would normally set the code and lamp after so many hits.
However there can still be a long term record in phase 6 that 'might' point to the cylinder causing the missfire.
You have to go at this from a knowledge point or your just guessing and waisting money and time.
This is what the forum is for. Don't go with a lot of comments based on a wide range of things unrelated.
These sytems are a lot more complicated than most realize such that simple answers are seldom correct..
Good luck.

 

I took my truck to real high performance racing shop and they attached a scanner to it. Four out of eight of the new coils were bad. The guy gave me 4 like new coils, I put them on and the truck runs great. I emailed the ebay seller and told them I'd like to return all 8 coils. I'm going to remove the remaining 4 coils 1 at a time and replace them with my old ones and test drive after each installation , that way I'll know that each coil is working.
thanks nick c

 

Live and learn man Just be happy it was an easy fix.

 

After being out of internet until now, I see your success.
Very often a mass replacement brings with it more problems either with the parts or workmanship slipups until total confusion sets in.
This is why trouble shooting must be addressed in a controlled diagnostic manner and with some knowledge of how the systems work.
Your shop did a good honest job.
Good luck.