Got me stumped

James Goforth · 2005-09-01T00:59:28+00:00

I've posted here before about a persistant miss on my '88 Z-24. Themiss is on #3 cylinder (pulling plugwire off #3 doesn't change idle,plugwire arcs). Miss is noticeable at idle more than at increased speeds but I senseit has less power than before during all rpms. I have a donor car I robbed parts from to try on this:1.) There were no codes.2.) I replaced the corresponding coil pack although the plug was firing,still is. No change.3.) I replaced ALL the injectors, although the old ones tested ok forresistance, & replacements all tested ok also.) No change, stillmissing on #3.4.)Found the egr valve to be stuck, replaced (there were no codes forthis). No change. 5.) Replaced the IAC motor. No change.6.) Took compression check on that cylinder: 150 psi.7.) Switched spark plugs between #3 and adjacent cyl; plugs looksimilar--whitish grey. No change.8.) Heads were replaced new last summer.9.) Finally took the wire loom that plugs onto injectors and swapped itwith the one from donor car--then I could have SWORE that fixed theproblem--and maybe it was my imagination--but after driving about twentyminutes, back to missing on #3 again. ANY HELP APPRECIATED. Thx in advance.

Got me stumped

Sep 01, 2005 20 Replies

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That book I referred to was just a reference book from a Sears Auto Center. I'm sure they get their oil recommendations from somewhere reputable since there are liability issues if they used an incompatible oil. I don't remember what other weights it recommended but I just remember it said that straight 30 was acceptable in the absence of multi-grade (only in warm climates, obviously, which mine is). I'd read in a Hot Rod mag years ago that straight weight afforded superior protection versus multi-grade, i.e. 30W versus 10W30. So I always used it in my '67 Buick GS400 convertible, (only driven in summer also).