1997 f150 engine trouble help!

[zig840]

1997 FORD F150 V6 4.2 MIS FIRE CODE AT CYLINDER 6
Got a serious problem here, hope anyone can/will help! I have a 1997 Ford F150, V6, 4.2. Has about 180k miles on it. I just had a new reman engine (w/heads) installed. All components off old swapped to new. Put in new spark plugs & wires, ignition coil, fuel injector @ cylinder 6, and a water pump. My machanic is getting an error code that shows a mis-fire @ cyl. 6, (which is why we replaced the plug wires, coil, and fuel injector. When the engine is comming to an idle(stopping at a stop sign),it shakes and shudders like its going to die but does not. When driving, it seems to run good, may shudder a little, until you start to slow down then it shakes and shudders a lot. While stopped, if you hold the brake and give it gas, it improves the shaking 95%. I will replace the fuel filter and check for any vacuume leaks Saturday. Any other ideas as to what this could be? Computer maybe? Note: The engine light came on earlier this year, well before the engine replacement, showing the same code and had the shaking as well. I had it checked at a local shop where they couldn't find anything. I'm $2600 in to this one which has me over budget already. HELP!!!!

[novsun88]

What is the exact code number ex. Pxxxx ... You kind of have me in the dark. I can think of a few different things.

[97XL]

Shuddering at idle sounds like maybe a IAC issue? Idle Air Controller??

[04heritage]

Wait, What? You have spent $2500 on chasing down a misfire? Was the reman engine needed/part of your mechanics solution?


Have you checked the oil? Seen a few trucks spitting and sputtering before someone realized it was on the verge of seizing because it didn't have oil.

[zig840]

Not positive but think the code was PO031 MISFIRE. My mechanic called yesterday and wanted me to bring the truck back, said he new exactly what the problem was. Said he did not set the cam shaft synchronizer/sensor. He set it. Did not fix the problem.
I looked back at repair receipts over the years. Had a cyl 3 misfire in May of 2005. The IAC, Intake plenum, and PCV valve were replaced then. Also the throttle body was cleaned. Had diagnostics ran exactly a year later for CIL (NOT SURE WHAT CODE). The IMRC valve & bushings and Intake gasket were replaced then.
Thanks for the help.

[zig840]

Thanks. Had that replaced May of 2005. I know thats been a while. I'm pretty sure my machanic checked it. Thanks again.

[novsun88]

Originally Posted by 97XL

Shuddering at idle sounds like maybe a IAC issue? Idle Air Controller??

My thoughts were the IAC as well..