1996 suburban 350 vortec engine is missing.

[jimmydude]

This thing is giving me fits. It has a miss at idle and also when under load like pulling 4000 lbs trailer. It runs fair around town, but I can feel a slight miss all of the time. It also sometimes shakes at idle and nearly stalls. I put new wires, cap and rotor, plugs, egr valve. I had it put on a scan machine the guy said it has a bad valve guide on number 4 cylinder. ( I think he is nuts) That is where the miss is I guess. The plugs looked good when I changed them out. Compression test is within 5 psi on all cylinders. (150-155 Lbs) This engine has 207,000 miles on it and has never been torn down for any repair. This thing uses a little bit of oil but no big cloud of smoke at start up. Could it be the timing chain? I had a friend watch the rotor as I turned the crank shaft with a wrench, we guess that is has about 12° of play in the crank before the rotor begins to turn. Any suggestions will be great. Thanks, Jimmydude

[bwood]

I think there might be a problem with your description "2006 suburban 350 vortec engine is missing". GM didn't even sell the 350 in the US in anything. The 350 was last available in a Suburban in 2000. Do you have any pics? You mention having a dist, cap and rotor. The Burb engines in 06 don't have a dist. I'm going out on a limb and gonna say its has the Gen I Vortec 350, at 207k the dist gear may be worn. This happens with time because roller camshafts are made of a stronger/harder steel and although the dist gear is hardened, it still wears out. If you have time, post a pic. I also noticed this is your first post, welcome.

[jimmydude]

sorry this is a 1996. not my 06.

[truckdude239]

i edited te title to read 1996 sounds liek it is time for a new disabotor sound like th cam gear is worn out

[bwood]

You can get reman dist from your local parts store or you could just replace the gear:

http://paceperformance.com/index.asp...D&ProdID=72159

http://www.oreillyauto.com/EW3/Produ...&currentPage=0

[jimmydude]

This miss is sometimes hardly noticeable and at other times the engine almost stalls. It runs great at higher rpm and has good power. Replaced the distributor cam gear. Did not help. Checked lift at valves all are lifting to book specs. Cam does not appear to be worn. Any other ideas. The code that keeps coming up is miss fire #4. Thanks, Jimmydude.

[Josh]

Does the timing on the scan tool read within -2 to 2 degrees? May have to have a tech two to see it. I've had distributors, injectors, even had a bad ECM one time that was cutting out an injector circuit... Start by elimination, check spark on #4, then fuel injector pulse and see if anything is funny. These trucks are notorious for a bad injector poppet causing misfires and all sorts of issues.

Josh