Cutting out under hard acceleration

MDH5169

New member
Hi, let me apologize if this has been discussed under another thread.
I have a 91 syclone with 88k miles. It will fall flat on its face under hard acceleration but only for a second and it only seems to happen in 1st gear...after that it pulls as expected.
Truck is totally stock with no mods.
Thanks in advance!!
 

sy2639

Member
Make sure you have more than 1/4 tank of gas in the tank. If not all the fuel will slosh to the back of the tank away from the fuel pump pickup during hard acceleration.
 

MDH5169

New member
Make sure you have more than 1/4 tank of gas in the tank. If not all the fuel will slosh to the back of the tank away from the fuel pump pickup during hard acceleration.
Thank you, it is just under 1/2 a tank but I'll try topping it off and see if that helps
 

IGottaSy

Member
Are you using any sort of scan tool? I recommend this app called aldldroid and bluetooth cable. It lets you datalog.

Screenshot_20210124-220515_ALDLdroid.jpg

You can see it on YouTube.

It can be a few things. For example,

1. Weak fuel pump
2. Clogged injectors (if not driven often)
3. Broken spark plug wire.
4. ICM going bad or getting hot.
5. Clogged fuel filter
6. Old or crappy octane fuel(winter mix)
7. Loose grounds or wires( dirty batt terminals & such)

I'd check the cheap or free stuff first.

What's the background? Parked for a while? Doing after tune up? After cold start or after its hot?
 
If you're getting into knock from one of the fore-mentioned items by igottasy and it retards timing but knock continues it can cut ignition momentarily....ask me how i know lol.
 

MDH5169

New member
Are you using any sort of scan tool? I recommend this app called aldldroid and bluetooth cable. It lets you datalog.

View attachment 1864255

You can see it on YouTube.

It can be a few things. For example,

1. Weak fuel pump
2. Clogged injectors (if not driven often)
3. Broken spark plug wire.
4. ICM going bad or getting hot.
5. Clogged fuel filter
6. Old or crappy octane fuel(winter mix)
7. Loose grounds or wires( dirty batt terminals & such)

I'd check the cheap or free stuff first.

What's the background? Parked for a while? Doing after tune up? After cold start or after its hot?
All good things to check.
It has done this to varied degrees since I got the truck about 6 months ago.
Had some vacuum leaks which have been resolved and it had had good moments where it even spun the tires off a launch...it just seems a little sporadic
 

IGottaSy

Member
I've noticed mine runs funny when I drive it like a grandpa(I am one, BTW) for a while. Like the ECU tune sets in on cruiser mode. This means cruising fuel and timing is saved over the spirited driving by self learning which the computer is designed to do.
 
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MDH5169

New member
I've noticed mine runs funny when I drive it like a grandpa(I am one, BTW) for a while. Like the ECU tune sets in on cruiser mode.
I only get mine out about once a month but when I do I always make sure the pedal hits the floor at least once.
That is very interesting though
 

IGottaSy

Member
I'd drive it once a week at least to get it to operating temps. Moisture can accumulate inside everything and cause issues. Dont have to go far if you are worried about the mileage. Idling isn't a good option either as it's running at its leanest. Mine has 124+ K miles and runs strong still.
 

MDH5169

New member
I'd drive it once a week at least to get it to operating temps. Moisture can accumulate inside everything and cause issues. Dont have to go far if you are worried about the mileage. Idling isn't a good option either as it's running at its leanest. Mine has 124+ K miles and runs strong still.
Yes I know it is important to keep them running and driving. I don't worry a lot about the mileage, had a typhoon with just over 100k and it never missed a lick.
What is tough for me is that I have 21 other vehicles so getting each one out once a month is doing pretty well for me 👍
 

ZavzTy547

Senior Member
Hmm.. is your cat deleted? If so, it may be over-boosting in 2nd which will throw a code and cut fuel. Perfect time for a scan tool..
 
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