Okay, Im not sure what is going on with my 98 4x4 blazer?? It has a lot of miles (~160k), and has had tranny rebuilt recently. A few weeks ago I went camping, and took a canoe on top. Truck ran fine on the highway, then as soon as we got off the highway, it started "cutting out"..? It felt like I was taking my foot on and off of the accelerator, but I wasn't. It did that for a few seconds, then ran fine the rest of the weekend. Came home, and on Sunday afternoon was running an errond when it started to do that and died. I had just gotten off of the highway that time too. It started right back up, but died several more time on my way home. I didn't go on the highway anymore, and it seems worst at about mid throttle during acceleration. Like when I take off from the red light. I've tried pumping the gas, and also holding my foot steady.. neither seemed to have a noticable different effect.

Could this be the fuel pump of injector? It didn't seem to be electrical, as all other components continued to run, the tach did not jump, and it really felt like it was sputtering for gas??? No check engine light is on. Any advice as to where I should start?

Thanks in advance!
Nibs

 

have you checked the fuel filter?

 

My uneducated guess would be the "throttle position sensor" possibly going bad.

BTW, you can't "pump" the gas in a fuel injected vehicle, per se. Pumping the gas pedal only affect the throttle plate which allows more or less air into the intake plenum. So, by rights, we don't really have a "gas" pedal but rather an "air" pedal.

 

When was the last time you had a tune up?

Sounds like you are getting miss fires that could possibly be caused by failing plugs or wires.

If you cannot remember the last time a tune up was performed, I recommend doing one consisting of plugs, wires, cap, rotor and a thorough cleaning of the MAF sensor, throttle body, and EGR valve (with a new EGR valve gasket w/ integral screen).

 

Thanks for all of the responses!!

No I have not checked the fuel filter yet. It is on my list to do this weekend.

As far as "pumping" the gas, I just meant taking my foot on and off the "air" pedal If I had a sensor going bad, would it not cause a check engine light?

Last tune up... It's been a while. I purchased the blazer about 9 months ago, and replaced the air and oil filter at that time, but did not do plugs wires etc...

It just seemed weird to me that it did this once (On a very hot day) then ran fine for 3-4 weeks. Then started doing it again as I described, and seems to have gotted much worse.

I need to get a service manual on this thing... I guess I'll start with the easiest things first. Tune up, fuel filter, etc...