OK, 5.4 Vic swap guys...
My car hesitates and stumbles when first started. I start it to leave work and when I hit the accelerator, there is a stumble, almost stall condition, then it'll backfire and then rev. All clears up after car gets to Operating Temp or after driving 5-10 mins.
Any ideas?
Yes, I did get a tune on it.
Clogged injector? Coil pack going out? Bad IAC?
Is there anyway you can get a scanner with record/playback on there that will track all of the sensors? I have one but you can probably borrow one a lot closer (like at your work).
A bad bit of programming while it's in open loop?
Maybe, I'll see if I can borrow the VDR tonight and just record it at start up and make it act up.
VDR - Vehicle Data Recorder. Records up to 5 minutes of data and goes back 30 seconds prior to pushing the magic red button. Records all data processed by the ECU.
mine does that just a little. the condition is gone so fast i haven't bothered trying to figure it out.
and mine is just a minor stumble, none of that other stuff.
if it were megasquirt, i'd add a little to the cold enrichment.
Water temp sensor?
same one before and after the swap
unplug the temp sensor and see if that makes a difference.. also check the wiring to it. if the wires get pinched, it can cause the kind of weirdness you are describing.
How do your plugs look?
See if the problem disappears as soon as it hits closed loop. If so, there is a basic issue with coolant temp, MAF or MAP, dirty injectors, fuel pressure or the program.
We're goign to data log it today. I'll let ya'll know what we find out.
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