Anybody try put 87 octane after runing on 93 with H/C/I

[Slow5.0]

Well when I installed TFS heads and everything else I run into pining problem because I was using 87 and with heads and cam have to be 93 so I switched to 93 and pinging is gonne and I getting better gas milage
So I wandering what if i try 87 again ,boy I was right still run bad
It hesetate, and pining and everything else BUT sounds better at 1800 rpms, I still have 1/4 of gas in tank and I wanna see hows gas milage, with 93 and easy on gas in city I can get 130-140 miles for full tank
BTW before heads I could get only 120 miles ,than why with all that extra air and fuel I getting better gas milage,and Stang doesn't run lean

 

[Slow5.0]

BTW I will switch to 93 when I empty this tank with 87
This is just testing

 

[donjohn]

maybe you should get a tune ernie- doesn't sound like your getting that great of gas mileage. I get the pinging running 87 and i haven't done barely anything to my car

gcomfx runs a zex kit and has some pics and info -->Here<-- .
he claims it's really a clean kit, and it sure looks good... so, there you go.

 

[Venom351R]

stick w/ 93, its alot better for our cars plus if you bump the timming you have to run it anyway. Your gas milage doesnt look that great, maybe you do need a tune up or some new 02's. I was getting about 220 miles out of a tank w/ whats in my sig on the car and that was w/ bad 02's until I changed those as well.

 

[BlackVert]

So I wandering what if i try 87 again ,boy I was right still run bad
It hesetate, and pining and everything else BUT sounds better at 1800 rpms,

i have the "h" and "i", but no "c" and i also have hesitation with 87 octane gas. it is the worst between about 1800 and 2500 rpms. it feels like the spark is not firing or something. when i use 93 octane, it is much better.

i think also my car does not like whatever they add to the gas in the winter for emissions. in any case, my car needs 93 octane right now. in the spring, i'll try 87 again.

I still have 1/4 of gas in tank and I wanna see hows gas milage, with 93 and easy on gas in city I can get 130-140 miles for full tank
BTW before heads I could get only 120 miles ,than why with all that extra air and fuel I getting better gas milage,and Stang doesn't run lean

up until about a month ago, i could get 200 out of a tank on 87 (2/3 city and 1/3 highway). since the hesitation problem started, my mileage has gone down. now i am getting about 180 on a tank. go figure.

 

[Mrgreen94gt]

i have the "h" and "i", but no "c" and i also have hesitation with 87 octane gas. it is the worst between about 1800 and 2500 rpms. it feels like the spark is not firing or something. when i use 93 octane, it is much better.

i think also my car does not like whatever they add to the gas in the winter for emissions. in any case, my car needs 93 octane right now. in the spring, i'll try 87 again.

up until about a month ago, i could get 200 out of a tank on 87 (2/3 city and 1/3 highway). since the hesitation problem started, my mileage has gone down. now i am getting about 180 on a tank. go figure.

It doesn't sound like the gas change is actually fixing anything, just masking something. You probably need to run a code scan, check plugs, wires, coil, maybe even clean the MAF (even if aftermarket).

 

[95strokerPSU]

i have the "h" and "i", but no "c" and i also have hesitation with 87 octane gas. it is the worst between about 1800 and 2500 rpms. it feels like the spark is not firing or something. when i use 93 octane, it is much better.

What does hesitation feel like? I think my car might have been doing that too until I put 93 in it.

 

[BlackVert]

What does hesitation feel like? I think my car might have been doing that too until I put 93 in it.

have you ever run out of gas? it is sort of like that sputtering you get just before you run out.
or it feels like it is missing or the spark is not firing consistantly.
the curious thing is that it only really happens after the engine is completely warmed up.

It doesn't sound like the gas change is actually fixing anything, just masking something. You probably need to run a code scan, check plugs, wires, coil, maybe even clean the MAF (even if aftermarket).

i have done all that and more. the only think left to try is to finish replacing the spark plug wires (the passenger side ones are a pain). after that, i will have to take it to the dealership for an ignition system diagnostic test.

with 93 octane, the hesitation/missing symptom is almost completely gone.

here is the thread:
http://forums.stangnet.com/showthread.php?t=512141

 

[Mrgreen94gt]

i have done all that and more. the only think left to try is to finish replacing the spark plug wires (the passenger side ones are a pain). after that, i will have to take it to the dealership for an ignition system diagnostic test.

with 93 octane, the hesitation/missing symptom is almost completely gone.

here is the thread:
http://forums.stangnet.com/showthread.php?t=512141

This may have been covered in the other thread, but....
What kind of plugs are you running, and what is the gap set to?
Do you happen to have an intermittent check engine light while driving?

 

[5.0fox]

i run 88 octane and dont have a single ping, but i also have slightly lower compresion then stock and 10* of timing

 

[BlackVert]

This may have been covered in the other thread, but....
What kind of plugs are you running, and what is the gap set to?
Do you happen to have an intermittent check engine light while driving?

stock autolite, stock gap
no check engine lights ever

 

[Mrgreen94gt]

stock autolite, stock gap
no check engine lights ever

Damn confuzoring.

What is your timing set to?

 

[Slow5.0]

I never have pining with 93

 

[BlackVert]

Damn confuzoring.

What is your timing set to?

stock 10. i have a tweecer, so if i want to mess with the timing, i can do it there, but i haven't touched the timing yet since i am still working on this and the injector slopes.

i just noticed yesterday that i have a leak in the exhaust after the cats, where the h-pipe connects to the catback stuff. i wonder if that would have anything to do with it ...

 

[Slow5.0]

Well today I empty my fuel tank with 89 (burn all gas ) and I got 160 miles in city normal driving ,thats 20-30 more miles than with 93
Thats because it was runing leam (pining)
Now again on 93 and power is back

 

[BlackVert]

Well today I empty my fuel tank with 89 (burn all gas ) and I got 160 miles in city normal driving ,thats 20-30 more miles than with 93
Thats because it was runing leam (pining)
Now again on 93 and power is back

i'm with you. 87=poor performance and missing/hesitation. 93=good performance and almost no hesitation.

my other 4 spark plug wires are going in tomorrow. also the exhaust leak is getting fixed.

 

[HazMat404]

you guys need to learn what octane is. the higher octane is harder to burn, thus more compression is needed. the lower octane burns faster and sometimes actually burns too fast and doesnt burn in a uniform fashion. it actual starts to burn in different parts of the cylinder (detonation). you want to run as low as possible octane without detonation. if you are running higher octane then needed, you will end up needing to use it all of the time even tho you dont need to. read up on this article cause it gives good factual info


http://www.ricehatersclub.com/vbulletin/showthread.php?t=9836