Stuttering TBI

[Hubnut]

On my drive home tonight from work, the 91 Jimmy (350 TBI) acted like it wasn't getting enough gas. I stomped on the throttle and it puttered and putted, nearly backfiring? Cold here though (38 degrees). Any ideas? Fuel pump, clogged fuel filter? Or could it be something more serious? Idled fine though. Thanks.

 

[4xcrazy]

check fuel pressure, sounds like what mine did when my fuel pump was dying out, semi-rough idle, would not go into overdrive due to having to be hard on the throttle to keep it in motion, backfiring out the intake, sputtering, just overall ran like crapola.

change out the fuel filter first though, just to eliminate that, and because it is probably due for one anyways

 

[eagle mark]

Yes it sounds like a fuel problem. The last two times this has happened to me it was a severly worn cap and rotor. Cold weather brings out the worst in cars and trucks.

 

[Hubnut]

Thanks very much for the help. I'll start with the fuel filter and move on to in tank fuel pump. Sure is a noisy sucker. I can here it running.

 

[Chaddy]

I would check your plugs and wires first. Then fuel filter.

 

[Thunder]

If your pump is abnormally loud it usually a sign they are going out. Stock GM pumps are pretty quiet. They maks a low hum you can hear when you first turn the key on.
But usually after the vehicle is startede you cant hear or are barely able to hear them.

Have you checked for trouble codes. Do that before you start replacing parts.

 

[Hubnut]

Changed the distrubutor cap, rotor button, fuel filter and in-tank (holy crap that's hard) fuel pump. Still hesitates on hard acceleration. TBI bad? I'll check the timing tomorrow, but it has been fine. Don't know why it would change all the sudden. Any ideas??
Frustrated!

 

[corey6969]

I have a chevy celebrity that does that when the ignition module/coil packs get sprayed with water. A coil pack shorts out and kills 2 out of my whompin 4 cylinders and it bearly runs down the road. It spits and sputters and back fires till the water drys out and comes back to life, haha. Of course thats DIS igntion to.

So long story short, kinda, check the ignition out, maby a weak coil or mag pickup in the distrubutor. I also remember a pickup like yours i worked on one time that did something like that. It would run perfectly then randomly act up like your describing, sometimes even die. So my best guess is ignition problem

 

[bftank]

i'm with corey on this one. make sure your distributor isn't loose and you have the correct timing. if it's to far advanced it will pop like that. and like corey said open your cap and check condition of ignition control module for corrosion and replace if there is. good luck!

 

[McDOT]

One more to check... the alternator belt for tightness... was bitter cold here and the belt was slipping to the point of poor charging and low battery. First sign to me was the sputtering engine half way home and worse as I got closer to home. I finally pulled over about a mile from home on the theory it may be spewing fuel under the hood with a leaky fuel line or something. All dry under the hood but it stalled when I continued and left me stranded on the side of the road with a mile walk in -40 C. After towing home and testing the alt output it seemed fine and the battery tested low and faulty. replaced the battery and everything was fine until it got cold again. Then the same sputtering and the alt was showing low output at the gauge. I tightened the belt and away it went.. no problem since... this to on a 350 TBI. Hope this helps !