Goodmorning all,

Just put a comp cams 31-255-5 and lifters in my 88 302 F150.
Truck is still speed density, Autolite 25's, MSD cap, rotor & coil, 9mm FR wires, GT40 upper/lower, 65mm TB.
Also still hydraulic flat tappet. Put a new timing set (cloyes) and dampener, and water pump/tstat while I was at it.

Truck is idling fairly well, just finished up the 30 minute break in period with the ZDDP additive.

I'm getting a mild push/pull, kinda of stuttering at higher rpm (4000? 4500? Only experienced it once.) It doesn't seem to be any kind of interference issue, almost reminds me of ignition stumbling.

Ideas?

 

You need to let the computer adapt... as much as it can, this can take a half dozen drive cycles. So don't sweat any minor driveability issues unless there is noise.

 

That's what I figured. Should I go ahead and unhook the battery to do a full reset? I had it hooked up the whole time during the install.

 

Well that is not good... the battery should be the first thing disconnected when doing any work on the motor... otherwise you risk damaging the PCM.
But it won't make any difference now.. it won't help it adapt any quicker.

 

I'm still having this issue, any ideas?

Edit:
Let me fill in some info holes here.

Truck just ticked over 85K miles total. I have about 600 miles on this oil change, did the ZDDP break in additive and everything.
I'm getting a stutter/hesitation that starts around 4400-4500RPM when in drive, normally to reach this RPM while accelerating you have to pin it to the floor, but if you let it run into this stumbling area and let it upshift, the stumbling will continue to occur for a few seconds, then it evens out perfect.

 

Though I'm not completely read up on the subject, and I'm thinking this would have been mentioned, don't these engine controls have a rev-limiting feature at a certain RPM?

4500 RPM sounds a little high, is it really at that number, and does it happen when actually driving the truck?

 

Would like to see some shots of this on how you adapted this to your pedal/cruise & etc. (if retained)

Any codes? What water temp, fuel pressure/you got a gauge?

What do the plugs look like?

 

It looks like your edit may have answered part of my question.

I probably would be thinking that it was starving briefly for fuel, air, or both.

 

Yes this has a rev limiter, however that's at 5250-5500RPM.
It will rev freely to that in park.

I made the bracket that bolts to the TB to retain the cables, and modified the armature on the throttle to exactly replicate the open/close and rate of open for the TV cable for the transmission. I haven't yet re-worked the brackets to accept the cruise control cable, but i'd like to as it works perfectly.

No codes, water temp stays well in the lower area of "normal" on the gauge (the gauge does function).

Fuel pressure is between 41-37 PSI from idle to WOT.

I havent yet pulled the plugs yet - I'm debating replacing them just to be safe.

 

That might b an issue.

 

Truck has run fine from idle to red line for 2 years after the intake install and before the cam swap.

 

It could be an ignition related misfire but considering all the parts you have on the motor it could also be that it is running a little lean in that area as a result of the SD systems limitations. A wideband O2 would help diagnose that and an adjustable FPR might cure it but it may also be a sign that you are a hair away from needing MAF.

 

I'm kind of shying away from misfire for the sole reason it continues to stumble after an upshift - granted, not for very long. Could be wrong in that assumption.

I DID keep the original springs, rods, and rockers, and I was wondering if this could possibly be a symptom of valve float or something similar?

I'll have to look around for a wideband O2 sensor, any recommendations there? And I'll try and snag an adjustable FPR. I've been wanting one for years anyways.

 

I have a lightly used Innovate LC1 kit that I'd part with....

 

Not exactly sure how that will apply to my computer setup?