I have a 1997 F150 Lariat Super cab with the 5.4 motor, it is RWD and has over 240k miles.

I just purchased this about 6 weeks ago and I am beginning to regret it. hopefully someone here can help me fix it.

Anyway when I first purchased it, it ran fine...for about 40 miles then on the way home it started shuttering like a transmission problem but after reading some posts here I decided to change all 8 of the coil packs and spark plugs. It helped but it would still shudder intermittently. Afterwards I decided to replace just about the whole EGR system...The EGR Valve, The EGR solenoid, the EGR pressure sensor. at this time I pulled the Throttle Body off and cleaned the hell out of it because of the carbon build up in it. It ran great for 3 weeks now the shudder is back with a vengeance and it shudders at approximately 40 -50 MPH. I have also changed the Throttle positioning sensor and cleaned the Mass airflow sensor, and one of the Fuel injectors because when cleaning them I lost one under the engine.

I am getting O2 sensor codes for lean on bank 1 sensor 1 also if that will help. I also got a misfire code on cylinder 1 and switched 1 and 2 coil packs and the misfire went to #2 so I took back the coil pack to Oreilley's and got another, which stopped the misfire at that time.

The engine sounds great when it is not shuttering and I like the truck except for this problem.

One more thing, I took it to a mechanic that said he had a scope and 20 years of experience and he stated that he thinks its the fuel pump because there's a drop in pressure when he pushes the gas pedal.

Another problem that I think is related is in the morning sometimes we try to start the truck and it stalls right away but if I tap on the EGR valve right where it mounts to the TB it starts right up. It's as if the brand new EGR valve is sticking and causing this problem. I am going to try to take it back and get a new one. I have heard of new parts being defective but 2 parts in that short of time I have not heard of but it is a sign of my type of luck.

I hope someone can help me.

 

Very first thing is you have to list the codes set.
Second is you still have a bad coil causing the studder. Use Ford coils.
Third what is the fuel pressure?
Forth it is normal to see a fuel pressure change when the throttle is opened because the fuel regulator has vacuum control to change it.
When the throttle is opened the intake vacuum drops.
.
Leave the IAC alone unless you have idle or cold starting issues.
.
Fifth, your guessing to much about the troubles and changing parts and doing things without achieving many fixes.
With multiple troubles you are not separating one fault from another and this is causing you confusion.
This is why you ended up here.
Good luck.

 

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Very first thing is you have to list

In the beginning, I had EGR codes, Icannot remember the exact ones but it was insufficient flow and that led me toreplace the 3 EGR things and clean the TB vigorously. In hindsight, before I searched the internetand bought a scanning tool, I could have just cleaned the TB and the problemwould have most likely been fixed. However,my oldest works at an auto parts store and she gets a good discount on part so Idecided to flip the $150 and replace the parts while I had it all torn down. After I did that, it did run great for acouple weeks but evidentially it was not the problem. I had a misfire code on #1 cylinder butreplaced that coil pack with another and it went away for a bit. I just replaced the EGR valve (it was underwarranty) a half hour ago and had my wife take it for a test drive (it is hertruck) she called and said…You guessed it, it is still shuddering. ^*%#^@ I haven’t checked the codes since I clearedthem last week because I have not worked on it but as soon as she gets home I willand post the results.



You mean the expensive ones The shudder is the only problem that I haveand it is driving me crazy! <o></o>

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Third, what is the fuel

With the engine at idle the fuelpressure is 28 PSI, with the engine off but key on (cycling pump 3 or 4 times)pressure is at 36 PSI, after 1 minute it drops to 34 PSI. However, I rented a pressure gauge from theauto store and the fitting seemed loose so it may not have been perfectlyaccurate. <o></o>







Yeah, I noticed a slight drop of afew PSI when throttling.<o></o>

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Leave the IAC alone unless you have

Sometimes in the morning (everyother morning) it starts and stalls real quick (a second or 2) if I tap on theEGR valve right where it connects to the TB it will stay running. This seems like an EGR issue so I will takeyour word for it.<o></o>







You got that right! I am guessing way too much, not only that thesupposed mechanics that I am dealing with, the darn scanning tool, and theinternet is pointing me in all different directions and that led me here inhopes that the next time I spend money on this truck, it will be fixed for awhile longer than 3 weeks.<o></o>

Quote:

Good luck.

Thanks, I need some good luckbecause all I have had so far is bad!<o></o>

 

The only code I am getting right now is the P0133. O2 sensor bank 1 sensor 1 reading lean.

 

Code 133 is slow response time for the OX sensor bank 1 sensor 1 the forward sensor..
Replace the sensor for that problem.
For the shudder at the speed range of 45 and above, you are in OD at light throttle.
At this time the EGR is opening as requested by the computer.
The leans the air to fuel ratio into the 20 to 1 + range.
This raises the voltage requirements to fire the cylinders.
If one cylinder cannot fire the mixture it becomes a misfire you feel as a shudder.
Otherwise no code will be set for this condition because it's not a hard fault and clears as soon as you downshift of add a lot of throttle that closes the EGR and returns the mixture too a richer condition the coils can fire ok.
Good luck.

 

How do I find the correct coil pack that is not working correctly, is there a trick that does not require a scope? Or do you think its all of them?

Should I change them all?

I know you said to purchase Ford coil packs but would the ACCEL Super Coil pack work better. If not then I should buy the Motorcraft coil packs?

 

I have no faith in ACCELL coils from experience.
The only way you can detect what cylinder is the cause is by using a Scanner capable of looking at diagnostic mode 6, test 53 at the misfire monitors for all the cylinder.
The one or ones with the high counts are suspect.
Always check boot and wire condition.
Good luck.

 

Go with the Motorcraft coils as Bluegrass stated...

 

When you changed the spark plugs, if you used dielectric grease, did you just smear it inside the boot or fill with the grease? Too much grease may keep the spring inside the boot from contacting the plug tip. The grease is used as a seal from the boot to the spark plugs porcelain to keep water out.

 

Yes I did! I packed about 1 quarter inch of grease in each boot. Maybe if I clean the boots and coils the problem will go away? That would be great.

Thanks for the advice.