Alright, lets do this. I know this isn't easy, but I've searched a lot and not found any answers.
I said I'd never have an EFI motor but a '94 truck just fell into my life and I can use it so, lets try to make it run right. I'm pretty good at working on diesel engines, everything on the farm is diesel. This is only my 2nd EFI (my 1st was a tercel that was parked due to a 'random cylinder misfire) and 4th gas vehicle ever, so I'm lost on what is going on inside.
The issue is directly related to throttle position and after only driving the truck for 3 days i'm getting better at making the stumbling start/stop. Basically, this is how it goes: Starts fine, may or may not idle high. Sometimes I can start driving and everything fine. The issue starts when you release the gas pedal, the engine stumbles, maybe flooding? and will regain it's self if you push the pedal back down. Everything is always fine when you are accelerating (full pedal to the floor), but I feel there should be more power? (my g/f 84 22r has more power) When going down hill the engine runs very very rough stumble, bucking, unless you are going down a steep hill with your foot all the way off the gas pedal. So to re-cap full throttle accelerating: runs great, No throttle down hill: runs great, anywhere in between: runs awful.
Most times it idles fine, but sometimes it will change and be low and real rough and if you rev it it will sputter like it's gonna die, but wont. Even when running fine the throttle seems not very responsive/ slow to rev.
Like I said, I've just got the truck and it came to me with the issue. PO had had it in 2 different shops multiple times and all I can find out is the AFM is brand new. Throttle body looks like it's from an older truck w/ RTV slimming it on. Also brand new cat. Muffler is rusted out. I guess the PO said the issues just started one day and it ran well before that. Runs well 60% of the time.
I've not checked much. I took valve cover off, everything looks good. Dizzy could be replaced, but not bad. The rotor button moves lose on the shaft, but I don't know if that's a problem? I put a timing light on it and the timing is close to 5 but jumps around a lot. Going to change wires, cap, etc but I don't think that is it.
I believe it's unrelated, but it warms up pretty hot sometimes if you start driving and drive up a long hill slow. I think it's a bad thermostat but haven't replaced it. Seems completely unrelated to the engine running issues, and it's only happend 2x.
Ideas?
I said I'd never have an EFI motor but a '94 truck just fell into my life and I can use it so, lets try to make it run right. I'm pretty good at working on diesel engines, everything on the farm is diesel. This is only my 2nd EFI (my 1st was a tercel that was parked due to a 'random cylinder misfire) and 4th gas vehicle ever, so I'm lost on what is going on inside.
The issue is directly related to throttle position and after only driving the truck for 3 days i'm getting better at making the stumbling start/stop. Basically, this is how it goes: Starts fine, may or may not idle high. Sometimes I can start driving and everything fine. The issue starts when you release the gas pedal, the engine stumbles, maybe flooding? and will regain it's self if you push the pedal back down. Everything is always fine when you are accelerating (full pedal to the floor), but I feel there should be more power? (my g/f 84 22r has more power) When going down hill the engine runs very very rough stumble, bucking, unless you are going down a steep hill with your foot all the way off the gas pedal. So to re-cap full throttle accelerating: runs great, No throttle down hill: runs great, anywhere in between: runs awful.
Most times it idles fine, but sometimes it will change and be low and real rough and if you rev it it will sputter like it's gonna die, but wont. Even when running fine the throttle seems not very responsive/ slow to rev.
Like I said, I've just got the truck and it came to me with the issue. PO had had it in 2 different shops multiple times and all I can find out is the AFM is brand new. Throttle body looks like it's from an older truck w/ RTV slimming it on. Also brand new cat. Muffler is rusted out. I guess the PO said the issues just started one day and it ran well before that. Runs well 60% of the time.
I've not checked much. I took valve cover off, everything looks good. Dizzy could be replaced, but not bad. The rotor button moves lose on the shaft, but I don't know if that's a problem? I put a timing light on it and the timing is close to 5 but jumps around a lot. Going to change wires, cap, etc but I don't think that is it.
I believe it's unrelated, but it warms up pretty hot sometimes if you start driving and drive up a long hill slow. I think it's a bad thermostat but haven't replaced it. Seems completely unrelated to the engine running issues, and it's only happend 2x.
Ideas?
Last edited:
Wow? was it really that easy? No more check engine light or awful running. I also put in an older TEq thermostat a had that doesn't close all the way and that fixed the 'warm up to much during warm up' issues. Still need a new muffler, to install new parts and set valves. Still feel like there should be more power, but I think what was throwing the code and making it kill its self was oil in the connection. I guess what I needed to order this whole time was a Gasket.
