Gamefreakgc

The saga of the 3VZ-E engine continues. In today's episode, we will try and deduce why the truck "jolts" at high speeds on the freeway.

So I was driving down the highway yesterday, I had just merged on and was going at 60 MPH in 5th gear at about 2500 RPM, when suddenly my truck jolts, as though I had hit a small speed bump at high speeds. The weird thing is that prior to that, my CEL was on. I had just pulled the codes, got a 25 for a lean air/fuel ratio. Since it's not anything dangerous to run on, and I was planning to fix this weekend, I wasn't worried about. When the truck jolted, the CEL light turned off . It only happened once in 15 min of driving. It did it again this morning going to work, only once.

I first though maybe my battery terminals were loose, since that's how I reset the codes. I checked the terminals and they are secure, couldn't move them at all with my hands. I'm out of ideas. Anyone had this before?

vasinvictor

iTrader: (3)

I still suspect battery terminals. They need to be cleaned with a post cleaner brush. If you CEL is dying when it jolts, the whole truck electrical system is shutting down. You won't clear a CEL until you manually do it, or the code has been fixedso. Also a lean condition is way worse than a rich one. Running lean will cause spark detonation and internet combustion temperatures that are WAYYYY too hot. Could cause burned valves, melted pistons, etc etc. Usually a lean code is a vacuum leak.

Gamefreakgc

I didn't elaborate much on the lean issue, partly because there's more at play. Two mechanics at different shops have confirmed my truck is running rich, but a lean code is popping up. I think I just have a bad VAF or 02 sensor.

My terminals are kind of old but have dialectric(sp) grease. Would taking some steel wool to the inside of the connectors, putting more grease on do the trick? I did that about a year ago when I put on the new battery but the connectors are old. If that's all it is, it's a sigh of relief. I was afraid something terrible happened like an object in the fuel line passed through my engine or something.

Nailit69

I had a '94 p/u w/the v-6 that would do that sometimes, turned out to be the ground. Make sure they're all attached and in good shape. Might just want to put NEW cables in, it solved my problem.

Gamefreakgc

Thanks for the help guys, I'll double check the ground and battery terminals and clean them off real good. I'm no electrician, so I hope a good cleaning will do the trick since I'm not confident rewiring the connectors.

Alaska90

what do you mean by "jolts"?

rpm increase? decrease? lack of power? increase of power?

kfj

My truck would do the same thing and my first two ideas were fuel filter, or how it was firing. I checked the spark plug wires, there was a couple that didn't look quiet right so I replaced them all as well with the distributor cap and rotor. The rotor looked real bad. The hiccup went away. I think I could have just got away with the cap and rotor.

Some days previous to repair, I wouldn't have a problem at all. Some days the jolt (As in lost power. It would drop in speed for only 2 seconds.) would happen 3 times. It didn't matter my rpms; I could be turning a corner. I hope this might be helpful. Think simple and stay positive.