2000 blazer hesitate/sputtering/surging
#11
Nsxmstng, I've used a timing light on older cars to do timing, can you explain what I should do am I just looking for missfires? It doesn't really do it in Park or when idling. I did replace the entire distributor, and the gears looked just fine on the old stem, no strange wear or anything like that.
I took it to my local shop, and had him take a look at it. He put a fuel tester on it, and drove it with the fuel pressure tester taped to the window, and said the fuel pump is fine. He drove it under load up hills and it never has a problem.
Also I forgot I also have replaced the EGR valve, and the TPS.
He does feel very strongly however that the problem is misfires, not fuel pressure or delivery related. So back to square one, the symptoms are:
Random stutters usually at lower RPM's, typically not under load. I can usually floor it, downshift and it will stop stuttering when it jumps up to higher RPMS. I'd say the stuttering only happens under 2.5k rpms. Some days it's really bad, other days it almost seems to be gone.
The engine isn't throwing any codes that I know of, if it was misfiring wouldn't the ses light come on?
Anyway, I'm open to any suggestion, even parts I've already replaced.
This thing is killing me.
I took it to my local shop, and had him take a look at it. He put a fuel tester on it, and drove it with the fuel pressure tester taped to the window, and said the fuel pump is fine. He drove it under load up hills and it never has a problem.
Also I forgot I also have replaced the EGR valve, and the TPS.
He does feel very strongly however that the problem is misfires, not fuel pressure or delivery related. So back to square one, the symptoms are:
Random stutters usually at lower RPM's, typically not under load. I can usually floor it, downshift and it will stop stuttering when it jumps up to higher RPMS. I'd say the stuttering only happens under 2.5k rpms. Some days it's really bad, other days it almost seems to be gone.
The engine isn't throwing any codes that I know of, if it was misfiring wouldn't the ses light come on?
Anyway, I'm open to any suggestion, even parts I've already replaced.
This thing is killing me.
#12
I wanted to follow up in case this thread ended up helping someone else. Based on another post here, and the fact the mechanic was sure it was misfires, I replaced the ICM, and it seems to have fixed the issue.
The clue was it seemed to happen more on days with high humidity or was raining.
The clue was it seemed to happen more on days with high humidity or was raining.
#13
How about the MAP
Manifold Absolute Pressure sensor ... just cleaned mine and its like driving a new car .... all my odd idle and acceleration issues disappeared instantly ... so I just ordered a new online.
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