So not sure what's going on... 2003 Disco II

Under hard acceleration it seems fine, but under light acceleration the engine seems to hesitate for a second. Seems to happen around the same RPMs every time, don't remember off the top of my head but I want to say maybe 2000 and again around 2050.

Like I said, light acceleration. Truck pulls, then goes just a little flat, then pulls, then flat, then does fine after that. No funny noises or knocking, doesn't sound like a misfire. Idles perfect.

That being said - I hooked it up to the Ultra Gauge, and it does show a "Pending" P1451. The Service Engine light never does come on, so the code doesn't ever seem to get "official".

If the weather stays nice tomorrow I'll probably do a compression test.

Any suggestions?

Thanks guys.

-Tim

 

Had a similar experience, turns out i had coolant running down a plug wire causing a misfire...so maybe in a dark garage/at night go out and see if you've got an arcing plug wire.

 

Scratch that. Code is actually P1451, not a misfire....

 

Check your SAI, there might be a leak in one of the pipes.

 

When was the engine last tuned along with new 8 mm silicone wires?
Have you cleaned your t/body? Could be the tPS is failing due to a burned spot.

 

1451 has to do with an open circuit to leak detection pump, deals with evaporative emissions. Maybe unplugged?

 

Thanks guys - Plugs and wires were just redone a few weeks ago. It does feel more like a flat spot in the accelerator than misfire, how do I go about checking/replacing the TPS?

I don't hear any obvious vacuum/blower leaks under the hood, will look at the SAI closer today.

Buzz - Any specific trouble spots I should look for on the Evap system?

 

Open up your copy of the RAVE and read up on both, there are pages about the TPS, and two versions of evap system.

 

Same for the TPS test, the Rave has full testing procedures.

 

Just wanted to follow up on this.

While getting ready to pull the spark plugs, one of the spark plug boots came off but left the metal spark plug clip on the plug. The wire was basically ripped right off. It looks like it had been that way for a while, the plug boot was burnt right through where the coil was apparently arcing into the engine block.

I'm guessing the previous owner did a tune up, and pulled the boots off by the wire instead of the boot itself. Checked the rest, and found one other boot that did the same thing.

I ordered a set of Mangacore wires, but in the meantime I needed to get this thing back up and running.

I went down to NAPA and picked up a new boot and clip for about $2.50, trimmed 1/2" off the wire to expose new core, and had just enough length to re-install them.

Took it for a test-drive, and it's running pretty good now. No noticeable hesitation. Will post after I get a better drive in later this evening.

-Tim