Weird problem.... No power?, bad acceleration?

4.0H.O.XJ · 05-28-2007, 04:59 PM

Man, this sucks.

Jeep idles (almost) fine, isnt overheating, good oil preszsure, no "check engine" lights, well maintained, 190k, all new sensors (MAP, 02, CPS, etc), all new filters good gas, .......

Gradually...I just have no power. Its acting like a clogged air filter or clogged cat converter. I gotta wind the wee out of it up to about 4K between shifts to get it moving. It somewhat (kind of) surges slightly at part throttle, and fuel mileage isnt what it should be: ABout 18 MPG. Operating it at part throttle or floored doesnt make a big difference as far acceleration is concerned. It just goes faster as RPMs build. Slowly. Feels like Ive got 10,000 lbs of weight I'm pulling around with it.

WTF? No clue. Well maiuntained, new filters, no smoke, no oil burning.....runs great until Im driving it.

Massive hidden vaccuum leak? New cat converter c;logged? Injectors taking a dump?

Any ideas would be greatly appreciated.

thx

**Matt Gertsch** · 05-28-2007, 05:06 PM

Sounds like a bad cat. It is pretty common on the XJs. Jeep used a huge batch of crappy convertors. Go to one of the many recall sites and see if you're entitled to a free one.

jfiscus · 05-29-2007, 09:27 AM

Are you getting spark to all the plugs & fuel through all the injectors?
When I put my new motor in my XJ I had 3 clogged injectors & it ran like a turd till I figured out what my problem was (REAL BAD GAS)

4.0H.O.XJ · 05-29-2007, 10:24 AM

My Cat is new(er, 6 months old). So, I dont think that's the issue, even though that is EXACTLY what it feels like

Im gonna check the injectors. Might explain the crappy idle as well.....
......So,....How do you check injectors?

jfiscus · 05-29-2007, 10:37 AM

Quote:

Originally Posted by 4.0H.O.XJ

My Cat is new(er, 6 months old). So, I dont think that's the issue, even though that is EXACTLY what it feels like

Im gonna check the injectors. Might explain the crappy idle as well.....
......So,....How do you check injectors?

Easiest way is to loosen all the metal snap clips first, then start the Jeep, then remove/replace the injector wires 1 at a time. If you notice no difference when pulling the wire then that cylinder is either not getting fuel or spark. Put the injector wire back on & check the plug wires for spark at that cylinder.