Cruise speed missing

Sneakysportsman · 08-05-2007, 02:32 PM

I am having missing problems at cruising speeds. I have done the following:
Changed plugs, wires, cap and rotor, Fuel filter, Checked MAP sensor, checked timing.
It dont miss at idle or while under load or hard acceleration, It happens during cruising and it is very noticeable in the exhaust tone. Any suggestions would be helpful.

mrjohnwayne · 08-06-2007, 02:22 PM

Check the cam position sensor. I've had one do that before and that was the fix.

Sneakysportsman · 08-06-2007, 05:50 PM

There is no cam sensor, its a 95 model, cam sensor came on 96 and up Vortecs

mrjohnwayne · 08-06-2007, 07:57 PM

ooppss.. my bad. Thought it was a vortec for some reason.

Sneakysportsman · 08-06-2007, 08:06 PM

Just has vortec heads. I am addressing a problem I had in another forum thread, that someone else is having and I think it might be my problem now.

Sneakysportsman · 08-09-2007, 08:23 PM

I have finally figured out the problem. Today I changed the plugs again, and this time i put them in the order they were removed from the block. Laid them on the table and went to crank the truck and again it was missing at throttle and cruising speeds. When I walked by the table I looked at the plugs and noticed a pattern. 1,7,4,6 all looked perfect. 2,8,3,5 all were gas fouled or burning rich. See the pattern? Injector on the driver side runs 2,8,3,5, these are the plugs that were bad. Problem- Injector firing too much fuel.

mrjohnwayne · 08-09-2007, 09:05 PM

Glad you got it figured out. I would of never though that.

Moostang · 08-10-2007, 07:12 AM

Now would that be a problem with the actual injectors or something else causing them to do that? I can't see all the injectors on one side going bad, I would think it was more computer related.. but of course I know nothing about Chevs..

mrjohnwayne · 08-10-2007, 08:10 AM

His is TBI. It only has 2 injectors.

Sneakysportsman · 08-10-2007, 08:24 PM

There were a few other things I founds out to day. The throttlebody is adapted to the intake, the intake is for a square bore carb, the guy who installed the adapter plate and flow matched all the internal surfaces didn't tighten the 4 bolts at each corner. Adapter plate to intake manifold gasket leak! next it had a serious backfire at on time, it blowed a metal reinforced gasket from under the TBI unit itself, another small problem. The back fire is caused from excessive timimg advance (28 degrees) is necessary for this cam. All these problems fell thru all at the same time, Coincidence or carelessness? I don't know.

08-05-2007, 02:32 PM	#1
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 296	Cruise speed missing I am having missing problems at cruising speeds. I have done the following: Changed plugs, wires, cap and rotor, Fuel filter, Checked MAP sensor, checked timing. It dont miss at idle or while under load or hard acceleration, It happens during cruising and it is very noticeable in the exhaust tone. Any suggestions would be helpful.

08-06-2007, 02:22 PM	#2
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,722	Check the cam position sensor. I've had one do that before and that was the fix. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

08-06-2007, 07:57 PM	#4
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,722	ooppss.. my bad. Thought it was a vortec for some reason. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

08-09-2007, 09:05 PM	#7
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,722	Glad you got it figured out. I would of never though that. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

08-10-2007, 07:12 AM	#8
Moostang Senior Moderator Join Date: Apr 2005 Location: Cali-4 Nye-Aye? Posts: 1,744	Now would that be a problem with the actual injectors or something else causing them to do that? I can't see all the injectors on one side going bad, I would think it was more computer related.. but of course I know nothing about Chevs.. __________________ Rock, Paper, Scissors, Lizard, Spock http://moostangproductions.com

08-06-2007, 05:50 PM	#3
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 296	There is no cam sensor, its a 95 model, cam sensor came on 96 and up Vortecs

08-06-2007, 08:06 PM	#5
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 296	Just has vortec heads. I am addressing a problem I had in another forum thread, that someone else is having and I think it might be my problem now.

08-09-2007, 08:23 PM	#6
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 296	I have finally figured out the problem. Today I changed the plugs again, and this time i put them in the order they were removed from the block. Laid them on the table and went to crank the truck and again it was missing at throttle and cruising speeds. When I walked by the table I looked at the plugs and noticed a pattern. 1,7,4,6 all looked perfect. 2,8,3,5 all were gas fouled or burning rich. See the pattern? Injector on the driver side runs 2,8,3,5, these are the plugs that were bad. Problem- Injector firing too much fuel.

08-10-2007, 08:10 AM	#9
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,722	His is TBI. It only has 2 injectors. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

08-10-2007, 08:24 PM	#10
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 296	There were a few other things I founds out to day. The throttlebody is adapted to the intake, the intake is for a square bore carb, the guy who installed the adapter plate and flow matched all the internal surfaces didn't tighten the 4 bolts at each corner. Adapter plate to intake manifold gasket leak! next it had a serious backfire at on time, it blowed a metal reinforced gasket from under the TBI unit itself, another small problem. The back fire is caused from excessive timimg advance (28 degrees) is necessary for this cam. All these problems fell thru all at the same time, Coincidence or carelessness? I don't know.

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