Slow response to WOT

I've got a buddy who has an 03 ext cab 4.8 that he swapped a 6.0 into. Since the swap the truck acts weird. Drives fine under normal driving usually. Sometimes it has very erratic shift points. We where logging to see what was going on and noticed when he goes wot the o2s and timing table waits 3-4 sec before responding. It doesn't even try to pull for that few sec. Then it'll pick up and run like it should. The tps shows 100 on the logs. We have swapped tb's and are kind of stumped. Ideas? Thanks!

Sounds like a tuning issue? Who tuned it?

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Originally Posted by AFSP1211

Sounds like a tuning issue? Who tuned it?

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^^^ Yeah Shawn.

Well, i guess since no one has any suggestions yet i will stir the pot to get some ideas flowing. Here goes nothing based on my limited knowledge and tuning experience.

I was originally thinking it must be a MAF or MAP sensor malfunction since the TPS sensor seems to be working properly and you swapped the tb. I was going to suggest failing the MAF and copy your high octane table into your low octane table so that the pcm would rely soley on the VE table, and see if that helps. If that fixed it then you would know that it was a MAF issue. If it didnt then i would be thinking MAP sensor.

However, since you mentioned erratic shift points that really makes me think TPS sensor. I dont know of much else that could cause both erratic shifting and very slow engine response to WOT. You swapped the tb though and that didnt help so surely its not the TPS sensor.

Which leads back to what has already been mentioned... who tuned it?? lol

Im gonna go out on a limb here and say that he tuned it, wish i could help man but idk anything about ls trucks.

Xp racing. It's done this since the swap. The drive there, while there, and since. Has also been back to have tune checked. Tune was checked and reflashed in case of bad flash. Then was taken to a shop in hennessy. They also checked tune. The tb was swapped once more to check and see if it was ok.

Fubar'd TAC?

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Originally Posted by Frenchy

Fubar'd TAC?

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hmm didnt think of that

Tune

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Originally Posted by ecld_07

Xp racing.

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There's the problem right here. I wouldn't let that little dweeb tune up my lawn mower