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Discussion Starter #1
i have a basically stock 88 gt, just installed BBK long tube headers with 40 series flowmasters and 2 1/2 inch exhaust all the way back. Do i need to adjust the timing, an if so to what. Having some heistation around 3 to 4 grand at WOT.
 

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The computer adjusts your overall timing at that point, only way to change that is with a chip and tune.
 

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I wouldnt mess with the timing. The exhaust is not the issue. It could anything from a flat spot in the TPS, fuel delivery (this includes sensors), or ignition troubles at higher rpm. Is it the same rpm everytime? When was its last tuneup? Any trouble codes? Connect a fuel pressure gauge so you can keep an eye on it at higher rpm. You will need a multimeter for the rest.
 

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Discussion Starter #4
All sensors have been checked, I keep her tuned up, I also puton a Mcleod clutch converstion kit with the slave cylinder, just got the engine resealed with all new gaskets, oil pump, timing chain,alternator, everything is new or have been through on the engine. Will try and upload some pics.
 

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Qwik Enuff
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The valve shown in your pictures with the hose open to atmosphere is called the thermactor diverter valve.It diverts (sends) smog pump air to the heads,through the crossover pipe,during engine warmup mode then diverts the air to the catalytic converters anytime the engine is at operating temp.With how youve got things setup in your pictures,youre diverting air to the heads during warmup,but diverting it to the atmosphere at operating temp,which is fine if your converters are gone.
If youve got converters on your new hpipe,all of the smog components are needed,in order to make the converters function correctly.Without those components,the converters will clog & fail.
If your converters are gone,all of the smog components can be removed because they dont serve any purpose now.

The information above is just a small tidbit of how the diverter valve works.The following link explains,in great detail,how the thermactor(smog),converter & egr system works in the Foxbody.Once you open the link,scroll to post #10 & start reading.
https://www.stangnet.com/mustang-forums/threads/wtf-egr-valve-plugged-in-but-no-vacuum-hose-to-it.477938/

A koeo/koer test can/should be run to see if any codes are present.These tests should always be run anytime you replace a mechanical part,sensor,etc to make sure the ecm accepted the change & no problems were caused (i.e.-vacuum leaks,etc) by adding the part.
Was the hesitation present before adding the LT's or did it not occur until after the installation??
 

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Discussion Starter #8
Cats are gone, ran for codes yesterday, no codes present, Now i'm getting this poof,poof sound, sometimes under throttle while driving, doesn't make the sound sitting still under throttle
 

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2016 Ford Mustang V6 lots
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How many miles are on this engine.?

Reason I ask is there could be the cam is flattening out and the poof poof noise is not usually a good one unless shifting and some unburnt fuel makes it into the exhaust. other check is for the oil/water to make sure your not sucking some water or oil into system, does it burn clean (no smoke)? there could be some fuel starving going on if the pump and lines are not up to the task or if the filters are dirty. old gas is not good but usually will burn but can clog injectors or stick them open causing over fueling same if pressure regulator is sticky.

M
 

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Discussion Starter #10
Thanks for all the help guys, it was the fuel filter dirty and clogged, replaced got fuel system treatment, runs like new.
 

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If your initial timing with spout removed is at 10*, bump it up to 13 or 14 and listen for detonation and ifyu hear it back it down a degree. I have never heard of a fuel filter fixing anything, but glad it did for you.
 
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