Duramax Lifetime Supporter
Join Date: Oct 2016
Location: Maurice, LA
After reading and digesting all yawl's replies (THANK YOU ALL VERY MUCH) I did a bit more troubleshooting/diagnosing. The pulsing is at very low speed but low speed also equates to low RPM.
I read in another thread about a similar problem and it turned out the PS pump was bad. Most likely a stuck vane. This makes sense to me because at times it is more or less severe, so something changes.
I went looking for a method to test my theory. I decided that if it is the PS pump and it is RPM based I should be able to prevent it by keeping my RPM up while coming to a stop. If Im correct, the problem should not occur or would be significantly less severe.
I drove down an otherwise unoccupied country road at 40 MPH, took my foot off the throttle and shifted into neutral. I resumed the throttle up to 2000 RMP and used my left foot to brake............No pulsing. I did it three more times, same result.
I went back to leaving it in gear and the pulsing resumed and was worst when the RPM dropped below 1000 (equal to about 5 MPH.
I think I have a PS pump bad. I found a thread for How To (Thanks again Hook) seems easy enough; went to Rock's site, ordered a new pump, new Gates hoses (pressure and return). They will be here on Friday but I will be in Houston (Astros games), so I will do the work on Monday following.
Wish me luck!
2008 Silverado 2500HD CCSB LTZ Diesel
FASS 95 Lift Pump (with Baldwin filters), Edge Insight CTS Monitor on a Windshield Mount, Nicktane Fuel Filter Adapter w/ CAT 306-9199 UHE tertiary fuel filter, Bilstein 5100 Stock Height, MBRP Downpipe back 4" exhaust with muffler and FTE 30" resonator/muffler, Sinister EGR Delete, Tuned but wont say who did it, Bushwacker Bed Rail Caps, AMP Research Bedstep, Fumoto oil drain valve, Dorman PS Oil cooler, Pioneer AVIC 7200NEX GPS/Stereo, Air Lift LoadLifter 5000 Air Bags.
Last edited by 407driver; 06-09-2019 at 11:25 AM.