Repost: 96 Tahoe with drivability issues

[AK3E]

Current problem is low idle rpm about 500rpms. Idle seems rough to me. This started a couple days after a transmission rebuild. Another sympton is when I get to a range of 55-60mph the engine seems to cut out and right back on. At first I thought it was an overdrive problem but watching the tach I see that I am already in over drive. This has also happened at highway speeds of 70 or so intermittently. Replaced all the plugs, the wires ohm out with in specs. #4 and 6 plugs where fouled when I changed them. This vehicle has had an ongoing occurance of o2 sensor turning on the MIL light. The local service guys have turned it off for me several times. I purchased a reader for myself since this problem has started and in addition to the o2 sensor I am getting a camshaft position sensor code. Curious if there is something in this circuit that could cause this other than the camshaft sensor being bad and could the transmission repair in any way cause any of these systems. I stopped working on cars back in the early 80's and went to industrial mechanic stuff. )) So not really up to date on the OBDII stuff. Thanks for any help.

Today I replaced the camshaft position sensor, cap, rotor, bank 1 and 2 #1 O2 sensors. The thing still idles a little rough. The Idle rpms in nuetral are about 650. Took for a test drive. All seems okay with the sensors. After shifting into overdrive, at about 60mph the thing is still missing. By missing I mean that the engine seems to shut off for a millisecond, just enough to feel it in the drive train. I only took a short trip today. Tomorrow about a 100m trip so will see if any codes come back. Any one have any sugestions about this miss??
Thanks

 

[sasquatch094]

timings off??? sounds like something to do with timing dont it??? but dont listen to me tho, let someone else agree with me. lol

 

[AK3E]

Well timing could be but it happens once after getting to speed above 55mph then may or may not do it again for a mile or 15 miles. Just very intermittent. Also sometimes it doesn't happen at all. I've wiggled wires/connectors etc in the driveway and nothing.
Rick

 

[96ProCompTahoe]

doesn't the CPS have to be set with a computer? (or did you have it set?)

-is your MAF sensor dirty? could be getting the wrong air/fuel mixture.
-what brand of plugs did you put in it? these engines love the factory AC delco plugs.. even putting the "platinum" AC delco plugs in mine made it idle a bit rougher than normal.

-cheap cap or a good quality cap?

 

[AK3E]

I'm not sure about the CPS having to be set with a computer. I know that id did not come back as a code during my short test trip. The dist cap is Napa and the plugs are AC Delco platinum. Hmmmm maybe I will try OEM plugs to see what happens. But still the problem is the miss at 55+mph. One plug missing would not give me the jolt I'm feeling.

 

[AK3E]

I finally figured out my problem. When the transmission was put back in the harness from the camshaft position sensor was pinched between the bell housing and block. So back to the transmission guy tomorrow!

 

[sasquatch094]

HA, thats nuts.. how did u see that>>

 

[AK3E]

Well you had mentioned timing earlier. So I did some internet searches to see what it should be. With my Auto Tap I am reading any where from -8 to -32. Way off. Also the code came back for the CPS. So climbed up into the engine compartment (I'm short) with a flashlight and followed the wires out of the CPM straight into the bell housing block joint. ))

 

[sasquatch094]

hmm.. thats still crazy that it happened like that and that no other damage was done. (like more serious damage)