Ok, I have an 88 f250 with dual tanks. The truck has EFI.

I am getting some bucking and jumping. The problem is inconsistent and I am having trouble diagnosing it. I normally will get the problem when the truck is cold, and it happens at cruising speeds. It started right after I installed a new IAC, negative battery cable and fuel filter.

Since I noticed the problem, I have changed the distributor cap, rotor and plug wires, and the problem is still there.

I am getting error code 34 when I pull the codes, so I know there is definately an issue with my EGR. However, I don't really know if that would cause a problem like I am seeing. I would imagine that whether my EGR works or not might cause the truck to run poorly, but not to buck. It really feels like there is no gas getting to the engine during the bucking phases.

I read some other posts about this and people were talking about a pancake filter, an EGR restrictor plate, or the fuel reservoir for the crossover between the dual tanks. No one seemed to post what the final verdict was on the problem.

I don't think the problem is from my EGR though. When I started trying to fix this problem, I noticed the EGR wasn't connected to anything at all, and i still had the problem.

i appreciate any help.

 

When mine was bucking at speed and stumbling at a light the posts I read were leaning toward TPS.......however......I looked for mine and it's on the bottom of the TB.......so it isn't replaced yet.......I could feel it......couldn't get to the screws....
I poked around in there and I did remove the bonnet and cleaned and lubed all the linkages.......and I haven't had the problem since......
Go figure....lol

 

Motor mount? The driver's side was broken on mine...and it would buck like a bronco at 1800 rpm. Wouldn't really explain why its running lousy, tho, just something to think about.

 

I had a problem sort of like this....would run just fine and it drove me crazy for about three weeks. At highway speeds, or just cruising around town, it would intermittently and randomly jump and kick. I thought it was a bad TFI module (since it was a $20 autozone special). Bought a new one, took the distributor out, then realized that I didn't have the TFI wrench. Put the wires back on, lubed up the connections and rotor, made sure I had the distributor back in the right place, and put everything back in. Haven't had the problem since....which to me is completely wierd because I have no idea what I did.....anyway, maybe this'll help, maybe not, but play with your wires (make sure they're not touching, and if they're old, replace 'em), and put some dielectric grease on your rotor, maybe that'll do something

 

replace the egr, clear the codes and see what it runs like.