Hesitation Problems

[caylorray]

Sorry for posting a question about a Chevy with this being a GM site, but I've run out of options. I've searched and searched and posted on other sites with no luck. I hope it'll finally end here! Anyways.....

 

I have a 98 Blazer that recently started occasionally hesitating. It started out with just a slight hesitation, could barely notice it when driving slowly or stopped. Felt like small 'bumps' of hesitation. But in the last couple of weeks it has gotten worse. It's to the point now that a few times it felt like it was on it's way to dying, but hasn't died yet. Oh, important, it never does it until the vehicle is warmed up. If cold, it starts out fine, but after about 10 minutes the hesitation starts. It can be felt through all ranges of throttle, and from Park to Drive to Neutral and so on. I went ahead and changed the fuel filter, no improvement. I wouldn't think the fuel pump would be the problem or I'd get hesitation even when the engine is cold. One thing I've noticed that accompanies the hesitation is a clicking sound in the general area of the distributor cap. At idle and in park, a clicking sound preceeds the hesitation, and then the noise stops as the engine recovers. I cannot pinpoint the source of this noise (that may very well be where the problem is). I removed the dist cap and cleaned the points, and on the rotor as well. I also inspected and cleaned the 'Idle sensor', the one next to the Throttle Position Sensor on the throttle body. Not sure if this matters, but the engine idles at 600 RMP. If I rev it up, it drops back down to 500 breifly, then back up to 600. No check engine lights at all (except when I've disconnected various components for troubleshooting).

 

Any thoughts at all?

[Mike G]

Sorry for posting a question about a Chevy with this being a GM site, but I've run out of options.  I've searched and searched and posted on other sites with no luck.  I hope it'll finally end here!    Anyways.....

 

I have a 98 Blazer that recently started occasionally hesitating.  It started out with just a slight hesitation, could barely notice it when driving slowly or stopped.  Felt like small 'bumps' of hesitation.  But in the last couple of weeks it has gotten worse.  It's to the point now that a few times it felt like it was on it's way to dying, but hasn't died yet.  Oh, important, it never does it until the vehicle is warmed up.  If cold, it starts out fine, but after about 10 minutes the hesitation starts.  It can be felt through all ranges of throttle, and from Park to Drive to Neutral and so on.  I went ahead and changed the fuel filter, no improvement.  I wouldn't think the fuel pump would be the problem or I'd get hesitation even when the engine is cold.  One thing I've noticed that accompanies the hesitation is a clicking sound in the general area of the distributor cap.  At idle and in park, a clicking sound preceeds the hesitation, and then the noise stops as the engine recovers.  I cannot pinpoint the source of this noise (that may very well be where the problem is).  I removed the dist cap and cleaned the points, and on the rotor as well.  I also inspected and cleaned the 'Idle sensor', the one next to the Throttle Position Sensor on the throttle body.  Not sure if this matters, but the engine idles at 600 RMP.  If I rev it up, it drops back down to 500 breifly, then back up to 600.  No check engine lights at all (except when I've disconnected various components for troubleshooting). 

 

Any thoughts at all?

 

<{POST_SNAPBACK}>

 

 

 

I would turn to new cap and rotor, perhaps wires as well. Maybe the EGR valve needs to be replaced. I was having issues similar to this on my big truck and rather than replacing a part at a time "hoping" to solve the problem, I broke down and spent $100 to have it diagnosed at the dealership. Cost me $20 more after that to resolve the issue...

 

--Mike

[JimsZR2]

Maybe it's a sign the fuel pressure regulator is going out?

 

I actually have the same issue but not as bad. I called the dealer and they want $221.60 for a new EGR!!!

[Jerther]

I would first check the timing using a timing lamp. the sound you hear may be caused by the ignition that is happening to much in advance (ping), and therefore causing the hesitation.