I've searched the forum without any clear cut advice so I thought that I would restart the conversation. The D recently threw the code P0207 - Cylinder 7 Injector Circuit fault. The symptom was a very short period of rough run - kind of like a missing cylinder. Makes sense to me. After the initial symptom the D ran fine. I cleared the code and went on my merry way. Eventually I received the code P0203 - cylinder #3. Again, same short-lived symptom and then moved on. This one actually cleared itself. I did not need to clear the code.

Here's the common thread to both codes - I was towing my 4000lb boat both times. My initial thought was that I must have had some gunk in the fuel tank that worked its way up and worked its way out. But why would that only happen under load? Any thoughts on this?

Thanks!

John

 

This could be a fun one to trace... Doesn't sound like a PCM at all... Could be fuel pump, could be needing a new filter (which IIRC is the same assembly as the pump.) Were there any misfire codes or just the injector codes? Try to measure the resistance of those two injectors against all others.... I can't think of much, but I am sure someone will pitch in!

 

Thanks for the reply. Please forgive my ignorance, but what is IIRC?

There were no misfire codes, only injector codes. In addition, only one code was thrown at a time. Code thrown, read codes, P0203, PDONE, clear codes. Code thrown, read codes, P0207, PDONE, code cleared on own.

I think the important thing to remember is that this ONLY happens when I am under load. When driving normal city or highway driving I have no codes thrown. So if it were the fuel pump or filter, what is different in the fuel system when under load than when not.

Furthermore, what about TPS or IAC? Do these components operate differently when under load? The engine would be working harder... I am going to replace the TPS as it is a cheap part to throw at the D. And it is the original one.

One last thing - the same code was thrown last year while I was trailering from the Keys to Clearwater. What changes in the fuel system when the vehicle is under load...?

 

you could try one of those in-tank injector cleaning things, you could have some junk caught up in the lines that the cleaner will get rid of.

also, how much gas was in the tank when the light came on? if you were almost out you could just have junk int he bottom of that tank which is somehow getting through the filter and getting lodged in the injector (my old truck used to throw misfire codes if i ran it below 1/4 tank i assume it was just the pump picking up contaminants)

how many miles on the truck? and what mods have you done (if any)? and when was the last tune up done?

and IIRC = if i recall correctly

 

Let's see-

There was over half a tank of fuel left when the codes were thrown.

No mods; pretty vanilla. Just shy of 89K on it. Last tune up has been a while ago... Probably five years ago for plugs and wires. Mileage-wise it has been about 20K. It's a third vehicle now.

 

well in that case im gonna suggest that you check all the plugs ont he injectors, upleg each one (the ones that gave you a problem) and make sure the connections are clean, then plug them back in making sure they are good and tight, (you can, and probalby should, check all of them while your at it)

and make sure that the crank position sensor is good (i think thats the one that helps control the injector timing)

 

Do a fuel presure test. There is a port on the drivers side. You want more than 50 psi.

Tune up.........

Go get a distributor cap and rotor with brass contacts. OEM wires. And get some Champion Truck Plugs for that bad boy. Route the a wires so they don't touch the engine as this is a TSB.

Stick with these name brands only.

 

Hydra,

Not to sound like a dumb-***, but is there a special guage that is needed for the test?

 

Yes, they can be had for cheap at most auto parts stores....

 

Hmmm... That's funny. I can't find anything specific to fuel pressure guage on AutoZone.com or Harbor Freight Tools websites...