Nathan Faunce

So I just finished building my engine, fresh build, .030 bore new titan performance head, comp cam 232 extreme 4x4 cam, bbk throttle body, the works, while doing the cam break in, I started getting intermittent surging sputtering and trying to die on me, I have codes p0135, p0353, and a code for vehicle speed, while doing the build I painted my engine but did not paint my ground studs as it would cause issues. I've gone through my grounds checked connectors, both o2 sensors are plugged in and I did not have issues with them before the build, I looked at the harnesses behind the valve cover as I've seen that is a common issue I didn't see any chafing, rubbing etc, when it starts sputtering is almost sounds like we have predetonation, adjusting the cps cleaned it up for about 5 minutes then it came right back, any one have these issues before or any ideas? It is a 2000 xj with an aw4 and the 4.0 just to clarify

Nathan Faunce

went through double checked all grounds again, timed the cps again, checked tps, checked vacuum lines, have not found any issues, one thing im thinking is i replaced the stock head bolts with an arp head bolt kit which eliminated the firewall to head ground position, my new head had a bolt hole for the ground there instead, wondering if its not grounding correctly, as it has to go through the head now instead of going straight to the block through the head bolt? also runs great at idle, at WOT it also runs great, my problem seems to be at a slow acceleration at the 2000-2500 rpm range sputtering and missing starts then tries to drop to idle and die i can pull it out of it by going to WOT

cruiser54

You can run that ground to a fuel rail bolt.

Nathan Faunce

my new head had a bolt hole for the ground however I was having issues with my could as the head gasket is not the best for continuity, I added a grounding strap from that bolt down to the engine block it fixed the misfire issue, other problem was my upstream 02 sensor was stuck in high range, got all those issues taken care of ran great for a day and my power dropped off fuel mileage went to **** and now it will not idle without my foot in the gas, will rev up but is running like crap, fuel pressure seems to drop off after prime thinking it's time for a fuel pump