My car hesitates in low RPM's 2500-4000, after 4000 everything seems fine. I know this is a commonly posted post, but I can't seem to nail it down, perhaps someone could help. It seems mostly in high gears (4/5) and it seems to only be present after driving for long periods of time. I've replaced the plugs/wires/coil. Now I'm thinking its either some bad wiring somewhere in the harness or the catalytics converter. I've had quite a few electrical problems in the past and I wouldn't doubt it being an electical problem because I can't seem to fix this problem for the life of me. I've also had problems with the car bogging down and clunking out on me... but I think that possibly has something to do with the crank sensor, I cleaned the connector the other day because it was covered in oil, havent have it buck or stall yet since. I'm also suspicious of the catalytic converter because several months ago I blew a turbo seal and filled the catalytic with oil so bad the car wouldn't even start, after awhile it all burned off and the car ran fine again. But I never really noticed the hestiations before that and also I have what sounds like an rattle comming from around the area the cat is. I don't understand why it would only hesitate in that RPM range though? any thoughts appreciated. thanks.

I thought I would also add that sometimes (once in 15) when I press the clutch to stop or coast RPMs stick around 2000-2500 and sometimes RPMs will drop very low and jump back up. At idle the needle bobbles a little but its barely noticable around 800, 1200 when cold, and sounds fine.

if you filled the cat meaign it was full of oil then that may be a contributing factor if ot the problem. take the cat off and shine a light into it and look. if it looks clogged then replace it.

when is the last time you replaced fuel filter? prob not it but you need to address that anyhow

idle issue probably a dirty throttlebody. remove and clean the IAC port.

any codes? is the CEL working?

you mentioned turbo.....is this a 4g motor or 420a...if 420a then what do you have for map protection? if missing link remove and clean it out.

Terry
96 Eagle Talon ESI....Daily driver

97 Eclipse.........

Fuel filter has been replaced twice in the last 30k mi, last time around 15k ago. I'm going to inpsect/gut the cat soon, but I don't think that is my problem. I'm also going to clean the the intake manny soon, I should have done it while I had the head off, because I blocked the EGR. It doesn't throw any codes that arent supposed to be there, code 21 for rear o2 sensor because I did a auto->5spd swap and never put in the rear sensor and a code 31 for EGR. I dont think these would cause hesitation. The car is no longer turbo, and I don't think 95's require any sort of protetion for fuel cut. I ordered a new ElmScan for data logging. Should help me with these stupid sensor/ecu problems. I'm starting to think there may be a bad ground or shorted connection causing a mess of electrical problems for me and possibly killing my ECU.

if you blocked off the egr, i doubt it would be your intake manifold. that will actually keep it much cleaner in there. it may be your cat though, if your valve seals are leaking. oil in the cat will kill it real fast. you said you had the head off, maybe a vacuum line is cracked or not tight. check your plug gaps too. hope that helps ya...chris

When I had low rpm hesitation is was an electrical issue. More specifically, a issue of grounding out some wires. Don't know if that helps, but I too changed the plugs/wires/and coil pack, but too no avail until I fixed the grounding problem, or lack there of.

Hope it helps.

Marc

I'm thinking I have a groud problem also. I have a shitload of electrical problems, and now I think it caused my ECU to go bad once again. The random sputtering then stalling is caused by the ECU. It clunked out the other day and I couldn't get the comptuter to output does with keydance, had to leave it there. Started right up later that day. Was your problem one of the grounding wires or a short? Anyone want to throw me some ideas on electronic diagnostics? I'm keeping the car off the road until I figure it out, as the problem is getting to be frequent.

This might help you guys help me:
I've had problems blowing the 30a ignition switch and engine fuses that are in the fuse box under the hood happened quite a few times about 3-4 months back, maybe once since then.

Also I can't put my windsheild washers on high without them blowing a fuse.

Rear windsheild wiper doesnt work anymore (assuming the problem caused the motor to go bad)

Low rpm hesitation

Random ECU failer/stalling

I think I've had other problems, cant think of them right now. I'll post if i remeber them.

Thanks

Problem solved I think. I checked all my wires and taped up any exposed wires and fix whatever looked like it could be a possible problem. I installed a used engine harness a few months back and quite a few of the connections had exposed wires, but they were wrapped tight and I doubt were the cause of the problem. The problem turned out to be a stray wire on the right behind the intake mani where the ground wire connects to the manifold. It is just a single black wire, so we thought it was a ground. With it hooked up lights in the car flicker and the windsheild wipers would blow a fuse when turned on high, I disconnected it and let it hang and all of the problems seem to have went away including the hesitation. Sadly the car is still incredibly slow. why do these things weigh so much...damn.. Thank god, I think this may be the last of my problems for the time being and I can focus more on other things in my life and make some new problems with the car... returbo soon enuf... pssssssst.