IPW dropping off during acceleration?

[Rawr256]

So a couple months ago I had the car running perfect with the basic I/DP/3.4/Tune setup on my 98 GTP, no KR or anything. The other day when I scanned the car I noticed it was getting a bit of KR on the top end of going WOT. Figured it could have been a fluke and did a few runs and they all seemed pretty consistent. I thought of possible false KR but couldn't figure out what it could be so decided to go up to a 3.6 pulley I had to see what would happen. KR is still present but not at such a large degree so I can say with almost 99% certainty it is real KR. Doing scans the O2's hang around 900 - 920 but the further I go in the RPM the O2's drop off and I noticed the IPW starts dropping, all seeming to happen right around 4500 RPM or so and on.

I went searching to see if there was something in the editor that maybe I missed or might have tweaked and not realized it but I can't find anything pertaining to the IPW other than the Cylinder skew.

The only thing I can think of is with the car rolling up close to 200k miles (193k atm) the injectors could possibly be getting tired or even gunked up and not keeping up. Filter on the car was changed maybe 15k miles ago after running a full can of seafoam through the fuel system so I would lean personally more towards the injectors getting tired more than them being gunked.

Any suggestions or anyone have any experiences with a similar issues?

[HawkZ28]

I'm leaning towards new injectors.

Change the filter anyway. 15k is just the time. My brother in law had one plug up and toast his pump with less than 10k on the filter.

[MMGT1]

I believe that IPW dropping like that is a sign that it's time to replace those injectors.

[highpsi]

With those mods you should easily be able to run a 3.6 with no KR, and usually a 3.4 with none also. Sounds like the car is going way lean.... Do you have a wideband? IPW is what the pcm is commanding, so something else must be wrong requesting to be leaned out... Do you have a log file you can post?

[Rawr256]

Hopefully this weekend I will be able to get the Wideband in and get a scan up. Didn't have the time or tools this weekend to get to it.

Hopefully will get a scan up the end of this weekend for people to possibly look at. When I compared my bin to an old DHP and a ZZP tune I have the only thing that is anywhere near fueling related that is really altered much is the MAF table, so almost 100% sure that it isn't something that I might have keyed wrong as far as number or decimal spot.

[e85grandprix]

Sounds like it needs to be re-tuned, could be a fuel filter, or not, i would start off with adding to the pe-vs-time table and see what happens. The injectors aren't "tired" that's kinda ridiculous... What do the fuel trims lock at when you go WOT, i'll be willing to bet it's not 0, or anywhere close to that, just sayin'

[Rawr256]

Trims lock in at 0%. Current fuel filter has less than 1000 miles on it and pump has maybe 25k. Haven't touched the PE adder vs fuel vs time ever. Honestly is a bit intimidating with so many damn columns and rows! Too use to the EQ ratio vs RPM on the wife's TA.

Would would I even start with on playing with in there? Know the more negative the richer it will get. Problem I guess I am wrapping my head around is the time part of it with the time. Does it basically jump back up to the 0 time and work its way down every time it hits that point on the RPM? Or does it keep running down the time and check against the RPM?

[HawkZ28]

I've witnessed ours go from a commanded AFR of 13.6 jus work it's way down to 13.1 when I get on it.

Honestly, I don't know that we can log the time component to properly set up a histo for that table.

24 seconds in PE.....I mean really! That's one hell of a steep hill you'd be climbing.

[Rawr256]

I've witnessed ours go from a commanded AFR of 13.6 jus work it's way down to 13.1 when I get on it.

Honestly, I don't know that we can log the time component to properly set up a histo for that table.

24 seconds in PE.....I mean really! That's one hell of a steep hill you'd be climbing.

Thats what I was thinking. Could also be cruising at some ridiculous speed that isn't safe for the typical stock suspension W-body too.