High speed miss?

Tiny
97SUBGA
  • MEMBER
  • CHEVROLET SUBURBAN
I have a 1997 suburban, 350 MFI, 230,000 miles,

1. It has has a hard shift out of first (tranny replaced last Oct. Never improved)

2. I replaced the Distributor, wires and plugs thnking the hard shift was a timing/ingnition issue that threw off the computer, Distributer was worn.

Reset the timing to TDC and pointing to "8".

3. Have a momentary studder/spudder that develops about 2300 rpm (I duplicated it in 3rd and 4th, nothing in first or second) under even pedal position. Not eveident under acceleration or deceleration.

4. Worked with someone and verfiied the tranny does not slip.

5. Disconnected the EGR problem goes away or barely noticable if at all.

6. Replaced EGR, connected and driveability issue (studder) came back- problem re-appeared NOT FIXED!

what are some suggested solutions? :
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Thursday, May 31st, 2007 AT 4:31 PM

2 Replies

Tiny
JACK42
  • MEMBER
1. Hard shift 1-2. There are a bunch of up dates for the valve body in that trans that will do away with the problem, trans shop should know this.
2. How did you set the timing? CPI injection has no timing adjustment, the dist must be lined up to #1 and the comp does the rest, if dist off, code will be set.

3 Have you ever replaced the 02 sensors or done a fuel pressure test? EGR open makes it real lean, if 02 reads off them it wont run well
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Friday, June 1st, 2007 AT 7:41 AM
Tiny
97SUBGA
  • MEMBER
1. I will take to a Trans shop, thanks

2. Actually read and executed Blancer mark to Timing cover mark, dist #1 to "8" on base, this takes #1 to TDC for the coorelation between Cam and Crank sensor and to your point does not set SES.

3. I have a OBD Scantool through my laptop it appears that my O2s are working I am seeing changes up stream of the CAT and significantly tighter voltage out on the after CAT O2s. I will work on the Fuel pressure test.

Thanks
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Friday, June 1st, 2007 AT 10:09 AM

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