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Re: Stumbles and misses when accelerating Posted by Saabina [Email] (#33) [Profile/Gallery] (more from Saabina) on Mon, 4 Oct 2021 11:06:55 In Reply to: Re: Stumbles and misses when accelerating, DaleG, Sun, 3 Oct 2021 13:20:12 Members do not see ads below this line. - Help Keep This Site Online - Signup |
When I had the same problem it turned out to be fuel pressure even though the car ran reasonably well and made several long west coast trips through mountainous terrain and generally ran OK as a daily driver. The irritating stumbling and hesitations were always around 2500-3000 rpm and under a bit of load like a long highway grade needing a downshift when it shouldn't be necessary. I replaced virtually everything (including the coil,) repeatedly checked for air/vacuum leaks and experimented numerous times with the timing, etc. Eventually I installed a fuel pressure gauge on the end of the fuel rail and noticed it was showing right around 30 with a 2.5 bar FPR. I then checked the fuel pressure on a strong running SPG which had the same exact setup and it was around 35. At that point, I swapped the fuel pump with the one from the SPG and the problem was immediately solved. The existing fuel pump was a Walbro that had been installed new several years earlier and appeared to be working well but was just not delivering adequate pressure under load. I hope you get it fixed!
posted by 99.75.88...
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