Engine hesitation
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Junior User
Joined: Dec 2003
Posts: 67
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Engine hesitation
Hi! I'm a newbie to this forum and I hope someone could help me with my problem. I have a '99 4.2 V6 and my engine have some problem on acceleration. I notice that there's some hesitation whenever I push my vehicle hard. I've already brought it to my mechanic and he run diagnostic tests and found no problem.
My truck already has new spark plugs, fuel filter and air filter. The mechanic has also cleaned the MAF sensor and fuel canister but the problem continue to persist!
The only problem that they can think of is maybe due to the quality of the fuel.
I use 93 octane unleaded. I've been thinking of using a 95 octane fuel but my mechanic discourages me because it would worsen the problem! Is this true?
Btw, I live in the Philippines and the only available fuel here is either a 93 octane or 95+ octane fuel.
My truck already has new spark plugs, fuel filter and air filter. The mechanic has also cleaned the MAF sensor and fuel canister but the problem continue to persist!
The only problem that they can think of is maybe due to the quality of the fuel. I use 93 octane unleaded. I've been thinking of using a 95 octane fuel but my mechanic discourages me because it would worsen the problem! Is this true?
Btw, I live in the Philippines and the only available fuel here is either a 93 octane or 95+ octane fuel.
New User
Joined: Dec 2003
Posts: 12
Likes: 0
From: Albuquerque
Yes, from what I've read, you need a lower Octane, or need to install a chip to advance the timing appropriately for the slower burning high octane fuel. The reason I say this is that I just bought a DiabloSport chip and had to switch to higher (premium) octane fuel. Somewhere during this process I read that using premium (high octane) fuel in an "87" octane "unchipped" vehicle could actually cause a loss of performance. Without the timing advance, the detonation would take place too late for the high octane slower burning fuel to completely burn - therefor a loss of power.
I don't know for sure, but it makes sense. Good luck!!
I don't know for sure, but it makes sense. Good luck!!
New User
Joined: Dec 2003
Posts: 12
Likes: 0
From: Albuquerque
Oh Yes - worth every penny!! There's a little more power, although hard to tell how much, but the raising of the shift
points in the automatic transmission to take advantage of
the engines specific torque curve is what really makes a
difference!! That's where the power and acceleration
improvement occurs. My engines max torque is around 3700 rpm
but it was shifting between 1800 and 2000 before - roughly
halfway up the torque limit. Now it shifts between 3700 and
3800 with the same amount of pedal, so I get up to speed much
quicker! It will still shift low, if you go real light on the pedal though. I forgot to ask them to remove the speed
limiter though, so I still have a governed 95mph limit, but I can
live with that. Most of my driving is around town, stop-n-go,
so the shift point mods alone are worth the money. For a
vehicle with standard transmission, I don't think there would be
near as noticeable an improvement though.
points in the automatic transmission to take advantage of
the engines specific torque curve is what really makes a
difference!! That's where the power and acceleration
improvement occurs. My engines max torque is around 3700 rpm
but it was shifting between 1800 and 2000 before - roughly
halfway up the torque limit. Now it shifts between 3700 and
3800 with the same amount of pedal, so I get up to speed much
quicker! It will still shift low, if you go real light on the pedal though. I forgot to ask them to remove the speed
limiter though, so I still have a governed 95mph limit, but I can
live with that. Most of my driving is around town, stop-n-go,
so the shift point mods alone are worth the money. For a
vehicle with standard transmission, I don't think there would be
near as noticeable an improvement though.
