Jimbo Slice

89 XJ/ 4.0L/ B/A tranny.

So on the tach at around 1700 to 2000 rpm my Jeep is a total dog in all gears with a random stutter thrown in as well. It's even worse going uphill, where I put it into the "completely sackless" category. Once I pass the 2000-2200 rpm threshold the power comes back and she gets up and runs again.

Dizzy cap, plugs, wires, air filter are all new within 1000 miles.

Fuel pump has been screaming at me for a year or so. Fuel filter has about 5000 miles on it.

Cat is nothing more than a chunk of platinum rattling around inside the shell.

Issue only occurs when driving and doesn't replicate when sitting in the driveway in neutral.

I have a new TB gasket and intend on cleaning the IAC and butterfly this weekend, as well as doing Cruiser's TB vacuum line fix.

Any other ideas?

cruiser54

That thing rattling around in the converter can roll to the back of it and shut the flow of exhaust down just like the ball in a snorkel.

A fuel pressure test is in order.

The Tips 1 through 5 are a "hafta".

Jimbo Slice

10-4 Cruiser, I'll have here in the garage this weekend.

1-5 have been done already, except for the C202 issue... because I don't have one.

I'll do them again though, along with the throttle body work and tip #6.

I also have the material to "fix" the cat, so that will happen as well.

Am I missing anything?

cruiser54

Fuel pressure test.

Jimbo Slice

Yes Sir, I'll report the results.

EDIT: So the problem only shows tangible issues under load and I can't replicate it in the driveway.

So... I need to set up a gauge and check pressure on the highway, or will a slight drop in pressure in the driveway equate to crummy behavior at road speed?

Jimbo Slice

Sorry it took so long to get back, but work has been crazy and I didn't get to work on it until today.

I pulled the throttle body off and cleaned it all up... as well as the IAC. They were both filthy. I also checked the butterfly setting... it was set right at .003. I put everything back together with a new gasket and took it for a ride... it has much better throttle response and isn't staggering up hills anymore.

I still plan on doing the fuel pressure test, just need to find the time. Will report results... eventually.

Thanks for the help!

cruiser54

excellent!!