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.