Need a mechanic for some diag

[Ed Gates]

I was wondering if there were any pros on the forum that could help me diagnose my jeep I'm having a problem where it starts cutting out at about 2800-3200 rpm it cuts out and it feels like it stalls for a split second it really throws you around a bit I do know the cat is bad it rattles and jingles

[Jim]

Check for codes.

Throttle Position Sensor (TPS) would be suspect on my list.

[Ed Gates]

No codes no check engine light last code shown was random misfire it's a '96 so first gen obd no memory

[94ToyBear]

Check fuel pressure when it happends. ( asumming its only while driving it happeneds)

If its a true 1996 it Should be OBD2. What is your 10th didget of your vin number ?

[Ed Gates]

Check fuel pressure when it happends. ( asumming its only while driving it happeneds)

If its a true 1996 it Should be OBD2. What is your 10th didget of your vin number ?

The tenth digit is T

[Ed Gates]

It is only when driving I can't replicate it without being under load

[Robert B]

what gear speed and where (mountain pass or flat ground) at first it seems like a fuel issue -- not enough fuel to keep it going .. and also is that near your redline or not ?

[Ed Gates]

Redline is from 5000-7000 it happens in any gear I can reach 3000 in so 1-2&3 terrain doesn't seem to matter

[94ToyBear]

It is only when driving I can't replicate it without being under load

Check fuel while replicating the condition.

Yeah its a 96.... strange that its OBD1 though.

[94ToyBear]

Did you fix the mis fire ? Or look in to it at all ?

Not sure if I'm just not seeing it.... I'm assuming its. 4.0l correct ?

[Robert B]

next Q is it a cable or rod system or does it have a tps ??? and have you done a WOT test ?

[Ed Gates]

next Q is it a cable or rod system or does it have a tps ??? and have you done a WOT test ?

Cable throttle TPS equipped and not sure what you're referring to on wide open test what am I looking for as far as running it up to 3 grand from the engine compartment to see if it'll do it yeah but no results

[Ed Gates]

Did you fix the mis fire ? Or look in to it at all ?

Not sure if I'm just not seeing it.... I'm assuming its. 4.0l correct ?

Its got a fresh tuneup wires plugs cap rotor and a new distributor oil/air filters it's got a new timing chain set and a few other things got changed recently too

[Ed Gates]

So does anybody have an 8' fuel pressure gauge cause I can't be in the engine compartment as well as the driver seat

[94ToyBear]

Its got a fresh tuneup wires plugs cap rotor and a new distributor oil/air filters it's got a new timing chain set and a few other things got changed recently too

Did you do all this work to fix this issue ? But it didnt fix anything?
I think it still a good idea to check Fuel pressure.. it kind sounds like your discribing what modern cars do to goven speed... on way they do that is cut fuel.
And hey if not at least you know that its good.

[Ed Gates]

I did all that to fix the oil seals front and rear and it needed the tune I'm curious if nobody suspects the cat that I mentioned is rattling like a can of rocks

[Ed Gates]

It does feel like a fuel cut

[Rick]

suspects the catCut it off and see if its better.

[Ed Gates]

"We don't need no stinking cat" exhaust is definitely in the works for sure

[Hypoid]

Cut it off and see if its better.If it has an O2 sensor after the CAT, it will set a light at the least.

I you can, pop the hood and take a picture of the VECCI label. It is on the rear bulkhead, next to the brake booster.

[Rick]

If it has an O2 sensor after the CAT, it will set a light at the leastI hit mine pretty hard on a rock and it started running like crap.... you could shake it and hear it rattling, cut it off and the c.e.l. came on but it ran the best it has ever run without that thing....put a new one on and issue fixed

[94ToyBear]

"We don't need no stinking cat" exhaust is definitely in the works for sure

A easy way to check if its the cat is blocking or pluged.... just pull the up stream o2 sensor drive it see it happends. If the cat was plane bad I wouldn't think it would be a big issue. ... you said rear seal... what rear seal are you talking about.

[Brad]

Could be the cat core is getting pushed sideways only at that RPM, you should see it happen off load though. I would suspect you have a dead spot in the throttle position sensor, should be a potentiometer and that too should happen off load. What about the Mass Airflow sensor? Does it have one? If so you could try unplugging it and driving to see how it runs. Of course when these go bad it generally idles bad too. Give those a try.

Sorry for the rambling, I'm tired. :D

[Ed Gates]

A easy way to check if its the cat is blocking or pluged.... just pull the up stream o2 sensor drive it see it happends. If the cat was plane bad I wouldn't think it would be a big issue. ... you said rear seal... what rear seal are you talking about.

Front and rear main oil seal timing gasket oil pan gasket I also welded and wrapped the header replaced the oil pump with a high volume unit(that was kind of fun had to massage the pan to get it to clear) out in new motor mounts I basically freshened up the motor as much as you can short of a trip to the machine shop obviously we had it out if there

[Ed Gates]

Could be the cat core is getting pushed sideways only at that RPM, you should see it happen off load though. I would suspect you have a dead spot in the throttle position sensor, should be a potentiometer and that too should happen off load. What about the Mass Airflow sensor? Does it have one? If so you could try unplugging it and driving to see how it runs. Of course when these go bad it generally idles bad too. Give those a try.

Sorry for the rambling, I'm tired. :D

I was kind of thinking that about the CAT I'm thinking that's when the gasses are moving fast enough to push the substrate against the outlet ill be checking into the fuel possibilities this weekend

[94ToyBear]

I was kind of thinking that about the CAT I'm thinking that's when the gasses are moving fast enough to push the substrate against the outlet ill be checking into the fuel possibilities this weekend
Try pulling the. O2 aswell

[Hypoid]

I was kind of thinking that about the CAT I'm thinking that's when the gasses are moving fast enough to push the substrate against the outlet Use a vacuum gauge to check for a plugged CAT.

[Rick]

on the CAT check temp difference on inlet side and outlet side...outlet should be hotter than the inlet by around 150 degrees.More than that indicates trouble with your engines air to fuel ratio.

[Ed Gates]

I'm fairly sure the CAT isn't doing a lot of anything the substrate is laying on the bottom instead of being fixed in place

[Rick]

the substrate is laying on the bottom instead of being fixed in placewell thats where I would probably start:2c:

[Geno]

if there is a O2 sensor below the cat it should be a OBD2 , OBD1 systems usually only have 1 O2 before the cat. if you can just unbolt or disconnect the cat back and go for a drive ( cheap test) cats do plug up and restrict flow, fixed 2 trucks with that problem already. If motor revs up fully and good power , replace cat(s) or if OBD1 CPU, run straight pipe, unless up are in a E-test area. We did this to Robert B. Blazer ( no E-test in El paso county), runs much better and NO codes. :2c:

[Ed Gates]

Looks like it was way worse than anybody thought it spun a cam bearing no oil at the rockers and the distributor won't come out sounds like a damn power stroke