My truck has developed a stutter or hiccup, most often while I'm in 5th gear and rpms around 2200. It sometimes only does it a couple times during a 10 mile stretch, no hills. Other times it can be every 5 seconds. I thought it only occured in 5th but there have been a few times I've shifted to 4th pulling 2600-2800 rpms and it would continue. Looking for so e obvious possible reasons. I've read a bad pcv valve could cause it, so I'm going to replace that on Tuesday. Vacuum leak, I've got a cracked plastic cap on one of my old emissions ports that I'll replace as well. Could a air bubble in the radiator cause this? I've had an issue with a leaking hose, not sure if it created a bubble but it's on the todo list to replace and refill the radiator. Another possible cause could be my muffler. I cracked it really good, so maybe my back pressure is the cause. These are the possible causes I can think of, looking for any thing else I can look at?

 

bad gas, spark plugs / gap, plug wires, distributor cap/rotor, coil, ignitor, fuel injector, fuel filter, throttle position sensor, coolant temp, head gasket... list goes on...

seriously though, if you haven't done the plugs/wires/etc., a basic tune-up may solve the problem.

 

Change the fuel filter.

 

Im running into same issue. My problem started with a hiccup here or there and over about a week or so it progressively got worse and now Im having problems starting it. Sounded like fuel filter to me. Changed the fuel filter and no help. Has new fuel pump and tank was clean when replaced. Just rebuilt the thing about 1000 miles ago. New plugs wires cap rotor temp sensor radiator exhaust timing is good when it idles right. Im lost.

 

Fellas, I had the same issue. It turned out to be the fuel cut selinoid on the carb. In the process of removing my smog, I had unplugged the plug for the selinoid. Once I got the plug back in,it runs great. No more hiccuping

 

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dbell: What are your running for your plugs/cap-rotor/wires? Have you shot the coil? I had a motor run poorly and it turned out to be the ground strap from the head to the body was loose. What do your plugs look/smell like?