'95 Mis-fire/"Hiccup" Please help!

Hey everybody!

I'm almost at my wits end chasing a problem I've had for the past month or so on my 1995 4 cyl 2.7L. This baby has 247k on it and has been like a best friend for me over the years. Up until recently she'd been running like a top with little or no issues with regular maintenance. Let me start all the way at the beginning...

My truck stalled out at a stoplight when attempting to accelerate. Unable to restart I towed the truck to my "favorite" shop. They replaced the plugs and were able to re-start but running very poorly and throwing a number of codes. The replaced the spark plug wires, cap and rotor. I picked up the truck and that is when I noticed the "hiccup" on acceleration over 1800 rpm. I took the truck back and they performed a full pressure fuel injection and system cleaning. This did not fix the issue either and he suggested an ignition module to the tune of $400. I declined as it wasn't throwing any other codes.

A day later the "Check Engine" light came on. I read the code and it was showing P0125 Engine Coolant temp sensor and O2 Sensor 1 Bank 1. I attempted to replace the Engine Coolant temp sensor myself but was unable to locate it. I ended up taking the truck to a different shop an they replaced the O2 sensor, it wasn't showing any other codes but still having the mis-fire/hiccup and he suggested replacing the fuel injectors.

I replaced the injectors myself and it was still having the problem so I took it to the dealer. They found a code stating that O2 sensor 2 wasn't working and replaced. They suggested replacing the plugs, wires, cap and rotor with factory parts (NGK/Denso) as they were all after-market for $385. I declined as I had just paid to have all this replaced and they were less than a month old. This evening after some research and suggestions to make sure I had NGK brand plugs in there I pulled the plugs I had and found that they were Autolite platinums. I pulled and replaced with NGK G-Power plugs. Still having the hiccup issue although there is a *slight* improvement in that it is somewhat less-severe.

Any help from anyone with some similar experience with this issue would be MUCH appreciated. I am very frustrated at this point and don't know what the solution is without replacing the cap, rotor, wires again into another expense. Everyone I know who has or has had a taco looks at me funny when I start contemplating selling it as I don't want to nickle and dime everything. Maybe it's time but I was hoping to get 300k at least out of it. Thanks for your time.

 

Well. I had very simalir problems with my 96 2.4. It was a #of things though. Plugs and wires. Had a mouse living in the air box. Also both ox2 sensors were bad. Plus my distrubutor was bad. So good luck. And sorry to depress you. But I have 265k and it still runs like a top. Actually way more peppy than my 2.7 4x4 with 150k less miles.

 

Thank you for the reply so far. I know that it can be fixed, I just wish I could narrow it down some more. I want this thing to keep purring.

Neglected to mention, dealer checked compression, fuel pressure, fuel pump, exhaust system, etc. All checked fine. Not showing any codes at this point.

 

An update on the progress. Ended up replacing an ignition coil with a factory one and that has fixed the hiccup so far. Not sure why. However, when I start the engine now anytime after the initial startup for the day, it takes some extra cranks to start and sometimes stumbles a second then runs just fine. Any suggestions? I just put some sea foam in the gas tank.

 

I had a problem with my 1995 2.4L...over 18 months ago. Hic ups for a long time, changed out plugs, wires, coils..nothing help, then head gasket went. I used Blue Devil on & worked until now, now I am getting price to fix. Then I will need to fix hic ups, I have sure cure for humans but not cars. Did you say you changed O2 sensor yourself, (only one) , how hard was it.....???

 

i'm having a similar issue - anybody figure anything out?
recently replaced sparkplugs and wires and o2 sensor bank2 (all from napa auto, probably not og manufacturer stuff) and that seemed to correct the misfire/hiccup for awhile. CEL stayed off for a minute with that.
but then I got PO115, coolant engine circuit, ignored it like a silly goose, then i overheated because I ran out of coolant (not sure why - should have checked coolant levels but was procrastinating, it was an original radiator so maybe it already had a hairline crack in it?)
I replaced the radiator and that seems fine but the hiccup came back. CEL off and no codes anymore.
decided to do sea foam and replace the coil packs. that seemed to lessen the problem, but it still hiccups lightly when the engine is under load around 3000rpm or hire. still no engine codes, though in the history was also PO300, general engine misfire.

i know my idle air control valve is wack and maybe my throttle control is loose or something...
going to do a compression test this week in case of a blown head gasket.

thinking of changing the fuel filter; i'm doing some patching work on the frame soon and have to drop the gas tank then so i may clean the tank out when that happens.
all the mechanics near me are booked out for months so i've been on my own with this for awhile and really have no answers either.