99 7.3 intermittent miss

[OBS-Addiction97]

I've been helping a buddy who's trying to fix his truck.. its a 99 7.3 with 400k plus. It has a intermittent miss under acceleration and will have a rougher than normal idle when the miss appears. It has a TS6 but its other wise stock.

Parts that we have replaced recently are new ford ICP with pig tail, UVCH and valve cover gaskets and a new fuel pump. Injectors are ford reman with approx. 100K on them. HPOP has been replaced in the last few years.

There is no CEL on. I scanned it with my AE and got P1211- ICP +/- than normal, P0470- exhaust pressure sensor, P0605 ROM error (I'm assuming from the chip) and P0478 -Exhaust pressure control valve high. passed CCT on AE. It passes all KOER self tests also.

Next step will be swap CPS, test fuel pressure to R/O a intank obstruction and then compression. A local shop is trying to push new injectors, but I feel the problem is elsewhere.

Any other idea would be appreciated.

 

[Justin@DP-Tuner]

Have you OHM'ed out the UVCH's? Were they Ford brand or Dorman brand?

An intermittent miss and rough idle always make be this wire harness issues.

 

[OBS-Addiction97]

Have you OHM'ed out the UVCH's? Were they Ford brand or Dorman brand?

An intermittent miss and rough idle always make be this wire harness issues.

Haven't ohmed them, but the uvch and vc gasket was ford.

 

[6.0 Tech]

Fuel pressure will throw the icp code a lot. Seen plenty of guys chase their tail "fixing" hi pressur issues that werent yhere for it to be a fuel issue, like yhe in tank filters.

 

[earlybroncoboy]

I know u say 100k injectors but I chased the same problem years ago. Replace the same parts. Put stage 2s in problem gone.

Does it do it worse on hotter tunes?

 

[OBS-Addiction97]

Fuel pressure will throw the icp code a lot. Seen plenty of guys chase their tail "fixing" hi pressur issues that werent yhere for it to be a fuel issue, like yhe in tank filters.

Thanks, plan on checking that.

 

[OBS-Addiction97]

I know u say 100k injectors but I chased the same problem years ago. Replace the same parts. Put stage 2s in problem gone.

Does it do it worse on hotter tunes?

I haven't completely ruled out the injectors, they very well may be the issue, but I just wanted to be sure of it before he went and bought brand new injectors when his might still be good.

 

[OBS-Addiction97]

Tested the fuel pressure tonight. Fuel psi would drop to 50 psi under WOT In the hit tune then hold about 55. Pis was 65 idling. Would a bad ipr cause this?