need help with engine/tranny problem

NeXuS1 · January 16, 2002

i'm pretty sure its just an engine problem, but i dont know.

when i push the throttle wide open, it'll rev to 2500 rpm and cut out and bog down to 2000 then rev up again. and just does an endless cycle while i hold it wide open. its never done that before.

next when i'm sitting at a stop right, the truck idles so horribly that the truck kicks just sitting there. like it rocks side to side a little. its not a constant thing, it'll idle smoothly for a little then kick then be fine for a little then kick again.

when i'm going down the road on the throttle a little the truck starts to jerk or serge, if i push it to 3/4 or wide open it goes away, and also goes away when i let off all together.

i have no idea what could be causing the problems, one person says my injectors might be clogged, another thinks maybe my fuel pump is dying. i'm lost, no idea whats going on. any ideas would be useful if anyone can understand what i was saying.

Shaners · January 17, 2002

fuel pump, injector (throttle body) or fuel filters would be the best place to start looking.

I'd probably start by getting some good injector cleaner and a new fuel filter. If that doesn't clear it up in a tankfull, then start looking at the fuel pump.

I ran the STP total fuel system cleaner in an old throttle body 350 I had and it made a noticable improvement. I think it is about $7 a bottle.

Do you get a check engine light??? It could be an Oxygen sensor or a mass airflow sensor. If you get the check engine light go to AutoZone and have them read it for you...

NeXuS1 · January 17, 2002

no check engine light. just replaced the fuel filter and air filter.

January 18, 2002

I agree with the two above responses. It sounds like fuel starvation.

01z71 · January 18, 2002

Had a similar problem with a Ranger. It was a dirty O2 Sensor.

NeXuS1 · January 18, 2002

me and a friend went ahead and jumpered the diganostic port deal to check and see if there was any codes stored, there was none. so today i'm going to go run this bottle of STP fuel system cleaner, see what happens.. after that i guess it comes time to start replacing sensors.

SoMnDMAX · January 21, 2002

Have a local shop check fuel pressure... Most likely, it's the fuel pump. Also, look at the injector spray pattern- it should come out the injector in a nice cone shape, and when it hits the throttle plates, the fuel should "boil" or bubble. Make sure both injectors are firing. Rev the engine up and continue watching the spray pattern, the injector pulse width should increase with engine RPM.

If there was a sensor problem, you'd have set a code by now, I would think.

I'm a former '90 K3500 454 owner... I've been down this road before...

NeXuS1 · January 21, 2002

got the problem fixed. went through ad replaced the cap, rotor, plugs, plug wires. got rid of the cheap 89 cent plugs. problem is now gone. glad it wasnt something too hard.. tho i hate changing plugs.

January 21, 2002

Cool beans!

Glad you got it fixed cheaply.

NeXuS1 · January 22, 2002

just took a long time, and was really cold. still cant feel my toes.

SoMnDMAX · January 22, 2002

Good to hear it's fixed.

Try changing the plugs with a set of Edelbrock TES headers installed..... The #7 and #8 cylinders are about IMPOSSIBLE to get at..... It definitely sucks!!!