LIM Gaskets Changed = Code 1345, Stumble, Runs a little Rough When Warm

[Tomfrmnh]

Hey guys. Chasing code 1345 on a '98 Tahoe. Recently did LIM gaskets and upgraded spider, new plugs, wires, cap and rotor. I've noticed the car runs ok, especially cold. After it warms up it seems to not idle as well especially while at a stop light and has a slight hesitation. The only code is 1345. Neighbor lent me his older SnapOn MGT2500. CMP shows -45! However, when I try and turn distributor there is no change. I know RPM needs to be above 1100 and I have been shutting off truck while turning distributor. As soon as I connect the scan tool up it registers CMP of -45. Wondering if that parameter is somehow locked in the scanner.

The truck also has a slight stumble while holding a constant speed (65 mph) after a load was put on the engine such as a slight hill climb. Just read an older thread where someone had the same symptoms and had injectors in wrong cylinders. (I'm sure I checked this 3-4 times) Kind of want to take care of code first before tearing into intake plenum. Any thoughts? Thank you in advance.

Tom

 

[lesterl]

Well, 1345 could be distributor in improperly, worn drive gear, etc.

You said you rotated the distributor, how much? There is a thread on how to manually align it without a scan tool.

I kept turning mine until the light cleared and stayed cleared. Had to advance it nearly a tooth (my new distributor I installed had a hold down bracket that would not allow turning, so I took my cutoff tool and cut the ears off.) My intent was to replace the hold down bracket with a chrome one I purchased at the parts store, but I got it running so good I don't want to chance the extra work.

Slight stumble (feel of a misfire?) has been plugs the last few times I have had it myself.

 

[Tomfrmnh]

Brand new AC Delco plugs, but I will take them out and double check them again. When I turn the distributor I'm turning as far as I can turn it.

As far as installation the truck is running descent. I just assumed that it was close enough. Would it run if it was a full tooth or more off? Maybe I should take it out and re-install with directions from local thread.

 

[Tomfrmnh]

Well, this is a little embarrassing. Decided to dig a little deeper and started removing plug wires from cap. Plan was to take the cap off and low and behold, I had forgot to plug in the CPS plug at the distributor. Plugged it in, hooked up scan tool and was able to get CMP at 0 to -1. I'm happy with that. Cleared the codes, took it for a drive and voila. That problem solved. Now let's see if the bucking was related. Thanks for the input.

Oh, code I was getting was not P1345, it was P0340. Gone for now. Thanks again

 

[lesterl]

Nice, let us know if there is anything else... Guess the -45 should have been a clue there....