surging

[low-keys89v6]

1997 4.0 v6. Had a CEL for the Cam sensor. Pulled it off and discovered the shaft was trashed. Replaced the cap and the shaft. I also replaced the serp belt and fuel filter. Truck started right up. There are no codes ( CEL lights not on) but the engine stumbles when braking just under 10 MPH. It runs great otherwise. Has a slight miss in park only. When in drive or reverse its smooth. If the truck does not slow under 10 MPH it dont die. Any ideas?
Im thinking computer or brake booster or cat converter. Remember...no CEL and runs great otherwise. lol.

I also checked for vac leaks,low coolant. Has new plugs and wires. Thanks for any input.

 

[low-keys89v6]

Well I read several other similiar problem using the search feature. Most were 5 speeds not automatics but the problem was about the same. Well maybe someone can just tell me if teh brake booster could be causing this. I figured if the booster is loosing vacuum at low speed (under 10 mph) then possible the kick down solinoid ( if this truck has one) is not working causing the truck to die. It does not do it everytime you stop and it starts right back up perfectly. hmmmmmmm

 

[modelageek]

1997 4.0 v6. Had a CEL for the Cam sensor. Pulled it off and discovered the shaft was trashed. Replaced the cap and the shaft. I also replaced the serp belt and fuel filter. Truck started right up. There are no codes ( CEL lights not on) but the engine stumbles when braking just under 10 MPH. It runs great otherwise. Has a slight miss in park only. When in drive or reverse its smooth. If the truck does not slow under 10 MPH it dont die. Any ideas?
Im thinking computer or brake booster or cat converter. Remember...no CEL and runs great otherwise. lol.

I also checked for vac leaks,low coolant. Has new plugs and wires. Thanks for any input.

was the issue withe the brakes there before you did the cam synch work?

 

[low-keys89v6]

It being my grandparents car they were iffy on details. I did not notice any problems with the brakes when I drove it after the repairs mentioned. While talking to them earlier they failed to state earlier that there was a diagnosis of some "sort" of computer issue but thats all they could tell me. I was thinking the master cyl. just because teh brakes are hard when the truck dies but im sure thats just because of the loss of vac pressure. Im leaning more twords the cat or the computer. They are happy with the way the truck runs I just dont like the idea of it randomly dieing on them. If you have any thouhts let me know. Thanks modelageek.....

 

[trail B2]

Do you think the cam shaft synchronizer you replaced is in time?If you think it's the brake booster plug or pinch off the hose and see if it idles better.

 

[low-keys89v6]

good idea...ill try that. I feel fairly confident it is on time. Its really close if not exact. I followed the instructions on TRS and the Chilton. I did not check the timing with a light afterwards tho. It does not stall every time. I really think its a computer issue or a sensor thats giving a false reading but has yet to throw a CEL. ty

 

[low-keys89v6]

Well the truck has started dieing every time you slow to a stop. It runs good otherwise. It only dies under 10 mph. If you slow and dont go under 10 it has no problem. I was thinking it was a fuel problem. The truck died and before restarting I checked fuel pressure and its good. Truck fires right back up. IAC valve?? Its not ramping up and down at idle. Raplaced anyway...still the same. Cleaned MAF....no codes but it dies. I really think its a computer problem. The truck stops like someone flipped a switch and fires right back up like nothing was ever wrong.....crazy.

Well, ill keep searching.

 

[low-keys89v6]

Well, after a few dyas of limited driving my grandparents decided to take the truck to deliver something. Anyway, it drove great. Idled good and never died. It seems to have fixed its self. Probably temporary but atleast it got them where they needed to go. If it acts up again im going to have to say its the computer.