High speed miss?

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? :

2 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

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