87 no trouble code has a miss skip in mid rpm range

[thomas haskins]

Ok 87 gn just got had issues from start trans rebuilt replaced turbo new maf plugs wires has a miss in it while driving at highway speed no trouble code from ecm checked for vacum leaks cant figure it out any suggestions i have always wanted a gn but geting irritated dont want to drive it with the miss any and all help would be greatly appreciated only does through mid rpm turn it up goes away idles sorta rough but has a approx 500 505 lift camaccording to previous owner

 

[RunninShine231]

hmm...... not going on much and letting us know an accurate cam spec helps. we can go from there. highway miss is vague also is it @ cruise speed, upon kickdown?

 

[thomas haskins]

Approx rpm 15 25 in all gears at that range i dont know exact cam specs speedo isnt correct i know that much i can take it out tommro and check exact rpms also doesnt do it all the time sometimes when u first start it does fine aftera little while it starts also it will stop sometimes when driving its not a constant miss just about every other second i am stumped on it

 

[thomas haskins]

Approx rpm 15 25 in all gears at that range i dont know exact cam specs speedo isnt correct i know that much i can take it out tommro and check exact rpms also doesnt do it all the time sometimes when u first start it does fine aftera little while it starts also it will stop sometimes when driving its not a constant miss just about every other second i am stumped on it

 

[RunninShine231]

what does scan master values show? appears problem is intermittent, swap known good coil pack. while your back there check your ground connections in back of cylinderhead on pass side, check the wires themselves everything be meticulous. you cant hang then drive a honda. dont forget ignition module also. once youve varified ignition side is good, simply continue testing she will show up.

 

[thomas haskins]

I was just looking for insight possibly someone else had this issue havnt had time to check grounds check while off this weekend and coil ignition situation car does not have scanmaster prev owner remove all the goodies before sale trying to recoup some of his money thanks for the insight let you know what i come up with

 

[longball]

[quote="Ok 87 gn just got had issues from start trans rebuilt replaced turbo new maf plugs wires has a miss in it while driving at highway speed no trouble code from ecm checked for vacum leaks cant figure it out any suggestions i have always wanted a gn but geting irritated dont want to drive it with the miss any and all help would be greatly appreciated only does through mid rpm turn it up goes away idles sorta rough but has a approx 500 505 lift camaccording to previous owner[/quote]

That's a long sentence (90 words) with no punctuation, kinda hard to read!

 

[Chuck Leeper]

As for: "you cant hang then drive a honda. dont forget ignition module also. once youve varified ignition side is good, simply continue testing she will show up." Maybe get your feet wet w/ helping someone, before you start bumping your gums??? [That's reserved for OLD farts, like me!]

You might take Longball's advice, too.

 

[thomas haskins]

Okay heres what ive found so far grounds are good check all off them i found i pulled coil off ignition gel looks like jello happensi orded a module so ill see what happens

 

[Chuck Leeper]

Suggest you add a coil pack to the order...Get the GENUINE parts.

 

[smokebeast]

Without going into too much detail this sounds like what is happening with me, I'm thinking spark/ignition problem too. Let me know what you find out. Also, any recommendations on plug/wire brands?

 

[Chuck Leeper]

Maybe, post up what you DO know about the car???
So far, all we have is: it's a GN, has a cam in it....
Suggest that before you ask for internet troubleshooting, you do/check the obvious.
Compression test.
Spring cleaning.
Some minimal scan tool readings.
Fuel psi.

Go to punctuation school.

 

[1fastcobra]

Okay heres what ive found so far grounds are good check all off them i found i pulled coil off ignition gel looks like jello happensi orded a module so ill see what happens

With a bigger cam ck the cam sensor. They like to be advanced a bit when running a bigger cam shaft ! If the coil&module are good

Posted from the TurboBuick.Com mobile app

 

[earlbrown]

Many many years ago I had an miss on the interstate. Turns out it was the TC converter unlocking for a millisexond and locking right back up. It felt EXACTLY like an ignition miss. The temp fix was to flip my TC lockup switch on. That forced the converter to stay locked up and the 'miss' went away.
The correct fix was to replace the 4th gear NC switch on the valvebody so the TCC circuit could stay consistent.

 

[smokebeast]

The correct fix was to replace the 4th gear NC switch on the valvebody so the TCC circuit could stay consistent.

Sorry, n00b question, but what/where is the NC switch, and is there a way for me to troubleshoot if this is the problem? My "misses" are always in 4th gear on interstate.

 

[earlbrown]

The 3rd and 4th gear switches are on the valve body. You have to drain the fluid and drop the pan to get to them. part number 8683502

reach under the car on the transmission and unplug the electrical connector on the side of the transmission. That will keep the torque converter from ever locking up. Put it on the interstate and see if the missing stops.

Or you can jump out the ALDL connecter with a wire forcing the converter to stay locked up.

 

[thomas haskins]

Okay i have been messing with the car some in my free time (what little i have) fuel pressure stays between 35 -40 starts doing it around 170degrees it doesnt do it all the time replaced coil module with another good used from a friend compression okay dont remember psi me and my cousin checked that all were close though changed fuel filters car has twin filters and pumps swapped computers no change have a crank sensor havnt put it on but i was thinking cam sensor im gonna try to put crank sensor on tommrow and double check cam sensor settings its not the converter locking up does it in all gears when it does it about ready to put it on a trailer and just take it and let somebody else deal with it but i know its something small im just overlooking the car runs to good the rest of the time i can go about seven miles from overnight cool down before it does it speedo gear is incorrect in trans as well i forgot to mention that

 

[TurboBuRick]

Don't give up know your getting warm.

Couple things to try.

1) Unplug the o2 sensor and see how it runs.

2) Try unplugging the cam sensor. Start the car. Unplug the cam sensor. Go for a ride. Still miss?

Both these will throw a ce light. No worries though. Just clear the codes after your test.

HTH

Rick

 

[thomas haskins]

Ok well i finally got i. I pulled the car in the shop let it cool off while i was mowing grass and jacked it up when i was done and i found the crank sensor had a small wear spot in it and was loose jiggling around so i replaced adjusted it fired it up and went to bed got up this morning let it run and warm up then went to a store about 9miles away didnt skip to or from so i guess that finally got it. I want to thank everyone for your help

 

[longball]

Glad you got it figured out!


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