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Ill try tomorrow to redo all the grounds, cant hurt.
Rpm drop when stopping.
- Thread starter Hodgeee
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it's possible but you would think after some time it would just flat out fail and / or throw a code, if this was something new happening then it would seem more likely.
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Been doing it for about 6000 miles. All the work was completed about a month ago to no avail.
Tried the braking from speed, same thing.
Noticed something i have never seen before. When coasting, between 5 to 8mph at the walmart grocery, the idle would do the same thing continously. It did it in nuetral also. Any faster or slower it would idle perfectly. I did not redo the grounds but did look at them, they all appeared super clean. This truck has never seen offroad before, or towed anything by the new and clean appearance of the entire underside and tow hitch. There appears to be 6 major grounds, from battery, engine block, interior fuse block, main wiring harness to the injectors and computer, and under the A pillar. looked good.
I was wondering, ive read about vapor lock and it was 101 out today, but in the last couple of weeks, with all the rain, its been around 70 degrees out, and it still did it. Just thinking the new thing was vapor lock.
Tried the braking from speed, same thing.
Noticed something i have never seen before. When coasting, between 5 to 8mph at the walmart grocery, the idle would do the same thing continously. It did it in nuetral also. Any faster or slower it would idle perfectly. I did not redo the grounds but did look at them, they all appeared super clean. This truck has never seen offroad before, or towed anything by the new and clean appearance of the entire underside and tow hitch. There appears to be 6 major grounds, from battery, engine block, interior fuse block, main wiring harness to the injectors and computer, and under the A pillar. looked good.
I was wondering, ive read about vapor lock and it was 101 out today, but in the last couple of weeks, with all the rain, its been around 70 degrees out, and it still did it. Just thinking the new thing was vapor lock.
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Checked fuel pressure, its the same as before the new fuel pump 43 to 48. It settles at 48psi, but with a lot of stop and go traffic, it goes up to 55 to 58psi which is high for the Flex motor. When this goes up, then my idle swings up and down at parkin lot speeds, and sometimes at idle. If i just drive a mile at normal pace, the fuel pressure goes back to regular. My chevy mechanic friend says its vapor lock which he says is common in Vegas during the summer, and a lot of customers bring theirs in to get checked out. This doesnt fix my brake issue, but what also can be done with the vapor lock?
I notice that the fuel lines are right next to the hot transmission, and go right by the exhaust. Surprising they routed it that way. Anyone else have this issue? Can I heat wrap my fuel lines, and will that fix it?
I notice that the fuel lines are right next to the hot transmission, and go right by the exhaust. Surprising they routed it that way. Anyone else have this issue? Can I heat wrap my fuel lines, and will that fix it?
Marky Dissod
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You could, not sure it'll address this symptom specifically, but can't possibly hurt.
I'm wondering if your alternator is just beginning to show the very first signs of aging past its prime?
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Tested, seems fine, charges at 14.4volts, plus new battery.
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I think i might have figured it out. Was going to redo the grounds since its only 91 out, mild for our summers. Decided to remove the throttle body for a deep clean, saw it was a Dorman. I know when you put in a new throttle body accordimg to my service manual, your supposed to do a relearn. So before anything else i followed the steps, and immediately the slow speed idle fluctuation almost dissappeared, and the rpm drop at braking only drops about 100rpms, and a couple times not at all. That is almost normal. The more i played around, the more the idle and braking acted up and got worse.
Its one of the few things i wouldnt normally replace, especially when tested good. I think the throttle position sensor in the new body might be bad or set incorrectly. I ordered a new ACDelco body and will get it next week. Ill report my findings after install and relearn. Worst case scenario it will be all gm original parts.
Its one of the few things i wouldnt normally replace, especially when tested good. I think the throttle position sensor in the new body might be bad or set incorrectly. I ordered a new ACDelco body and will get it next week. Ill report my findings after install and relearn. Worst case scenario it will be all gm original parts.
for $36 I would roll the dice just to rule it out
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$138, Acdelco, cheapest i could find.
I don't know if I would drop that much just to see if it is the problem, if you buy it off ebay and it's not the problem you can return it and get your money back.
