I have been having a fit with this and I have posted many many times. Question is Check Engine Lite is on steady at an idle, you drive it and it flashes. Is there a difference between steady and the flashes? Dumb question, I know, just curious.

 

In past experience, when the problem occurs, the light flashes to draw your attention to problem.. then goes steady after awhile/when you shut down & it stays in PCM. Will flash again once the same (or new) problem occurs again...(I have had the same code repeated on my OBD II code scanner). I know my truck drove like crap during & after codes were set (until it was shut down for awhile then restarted... then seemed to run fine until codes/problems started again. Hope this helps
Might be in your owners manual?
Cheers
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I'm pretty sure a flashing CEL means the OBD II has detected numerous misfires.
I think it is a sort of a "Hey, you got a serious issue going on here" kind of thing.

Have you had the codes read ?

 

I have 3 codes from Auto Zone..............P0174.........P1407........P0305 .........
I have changed, egr, maf, coil, plugs, wires, egr sensor.............what else is left except a new engine.........hehehehehe

 

My 97 was setting PO171( system adaptive fuel too lean - bank 1), PO174 (system adaptive fuel too lean, bank 2) and PO305 (misfire cyl 5) which I thought was the IMRCs at the back of the lower intake manifold at first...but listening to the advice here at FTE saying it is normally indicative of a vacuum leak, I tracked down two leaks after applying vacuum to all the small vacuum lines in the engine compartment - the brake vacuum nipple was holed/broken and a small vacuum line behind the battery tray (red line (EVAP?) plastic hose joiner at elbow was cracked). I couldn't believe that small amount of loss vacuum could set 3 codes continuously but it did (engine was indicating 19 inches of vacuum throughout the problem.
Did not have P1407 (no EGR flow detected) but I had checked my Electronic Vacuum Regulator & it was within specs, & I had changed my differential pressure feedback sensor (DPFE). I checked both Intake Manifold Runner Control ( IMRC) while I had the lower intake manifold off..cleaned the EGR passages as well (access to both requires removing plenum).
To eliminate #5 spark plug as a problem, I switched it with #6 to see if the problem moved. (Fixing the vacuum leaks made all the codes go away - fingers crossed they stay away).
Hope this helps
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Should I remove the plenum and clean all the passages, ya thunk.

 

Given that you've replaced just about everything else and checked all the vacuum stuff, and, as indicated by the number of postings on this site indicating plugged EGR runners it couldn't hurt. You could also check the IMRCs (sometimes the little plastic retainer bushings fall apart & the plunger arm drops out - it had on my LH bank) - Dorman (thru Rockauto) sells packages of 5 for $3 or so.
Bolts are really small & you will need a torque wrench in in-lb to torque it up.
Bon Chance (Good Luck)
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IMRC's, I never heard of these. I went to Rock Auto and did not find any listing for this. Its a 99 E-150 4.2 with 194,000 miles. What do the IMRC's do?

 

I might as well change all the injectors to since I am going this far.

 

IMRC Valve system controls the air intake charge by opening or closing the butterfly valve on the secondary intake valve directly at the intake manifold. By closing the butterfly to the secondary intake valves under 3000 RPM, low end driveability is improved - above 3000 the butterfly valves open to improved high-end performance. IMRC has a vacuum tube (blue on mine) as well as an electrical connector from PCM.
I checked RockAuto & they have the intake manifold vacuum retainer bushings listed for your vehicle but no IMRC valves? - if you want to see what they would look like, look under 97 F150 4.2 under engine section Intake Manifold Runner Control Valve.
Did you check out all your vacuum hoses/fittings in the engine compartment already?
Cheers
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What device did you use to check all the vaccum lines?

 

A hand operated vacuum pump -available at most parts stores- I disconnected at various fittings and checked each length of hose by putting my finger over one end (where possible) & applying vacuum to see if it leaded down. The little hoses are very prone to cracking/breaking I understand - NAPA has many types of jointers & u can use rubber vacuum hose to repair if you can't find (or too expensive) plastic tubes (coloured blue, black, tan, beige, and red - possibly more).
A Haynes repair manual (less than $20) is definitely an asset for fault finding.
Good luck
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Is there a difference in buying fuel injectors. Rock Auto has them for $30 vs some at $50.
I only want to do this once, and not have one crap out in 5,000 miles.

Thanks

 

I believe Brian would be in agreement & as I've found you don't normally go wrong with regard to dependability by using Ford (or brand name) parts, as the cost of parts is normally the smaller cost of repair. That being said, there are rebuilt (around $200 set) and new ones out there much cheaper & I believe it is possible to replace them with the plenum in place but it would be in extremely tight space & a lot more difficult than with plenum off. I did not change out my injectors, just both o-rings on each - but I do find that now, while listening to the injectors with a stethoscope, # 5 cylinder inj does not make as much of a metal-on-metal "clack/clang" sound as the remaining injectors do, so it may be weak/missing sometimes.
FYI, my Code PO 174 (lean fuel mixture, bank two) returned (no PO 171 or PO 305 code return yet) - Since then , I removed and cleaned the IAC and Throttle body, cleaned both and replaced gaskets and re-torqued. No code return on short test drive & I seem to have fewer codes showing up anyway (of course, that is with all gaskets replaced on the engine anyway)
cheers
Flagbagger

 

Update FYI:
After taking a short vacation, my 4.2 is again setting codes PO174 (lean fuel Bank 2 (LH bank) & PO305 (misfire Cyl 5). Took to Ford dealer & hooked it up to their computer - indicated coil is breaking down when engine comes up to temperature (cracked underneath being a common problem noted from FTE threads). New coil ordered & when replaced, hopefully the lean condition on Bank 2 will also have gone away - if not they will then be able to investigate that further.
I will get to use this vehicle yet!!
FUBAR
Flagbagger