1994 toyota pickup 4wd 22RE manual
No codes on dash
truck starts fine, soon as it warms up the idle drops to below where it should (800ish) and starts to almost die.
If i give it some gas, the RPMs go up and then fall 200-300rpms which can sometime cause it to die
Truck smells gas outof the exhaust, no smoke or anything like that. I should also note, when driving i let off the gas and the engine RPM drops below idle (200-300rpms), when i brake the truck tends to stall (losing power steering and brake booster). Not sure if this is a separate issue such as a vac leak or because my idle drops so low the vacuum needed kills the engine.

I've looked all over forums but no one has an answer, everyone is different. some say EGR valve, some say TPS, oxygen sensor, coolant temp sensor, MAF etc etc. But some of these should cause issues even when engine is cold. This seems like a temperature-dependent issue.

Ive replaced the coolant temp sensor - did not do anything
My guess is the oxygen sensor, but maybe the idle control valve. Any and all help is appreciated it.

My mechanic skill is 2/10.

 

How about just adjusting the idle screw?

 

I've done it, the RPM stays where i place it but as soon as i give it some gas it drops back down to 200-300rpm

 

Anyone?

 

Check for vacuum leaks, sounds like you might have one or more than 1. Check all your vac lines for cracks, check for one that's maybe disconnected, and also check the intake rubber elbows for cracks, not a vac leak, but unmetered air.

 

Engine was built not too many miles ago 20k miles ago with new hoses, i am doubting air-leaks. I have checked the elbow on the intake, looks good.

I've also plugged the EGR in the TB before and it still produces the same problem.

 

Sounds like you are on the right track but there really isn't anything to-do but to go over the air intake piece by piece, and thoroughly.

Make sure the vane isn't sticking in the air meter. No cracks in the accordion pipes, or the air valve hoses. Tps spring isn't sticking, and properly adjusted. Brake booster diaphragm, and check valve working properly.

Then look into a new o2 sensor, dirty on the outside is as bad as corrosion on the inside.

 

x2 on the TPS sticking or being improperly adjusted.

 

Update: I tried to take my TPS off but the screws stripped and so with limited tools i threw the white flag. I bought another throttle body from ebay and stuck it on. Also, i noticed that at times, when i pushed the gas, the RPM would not come down. Turned out that spring mechanism was sticky so i zip tied it all the way down. So far so good, but my truck is still running rich.

Currently thinking it could be the cold start injector, MAF and/or O2 sensor.

If the cold start injector is unplugged, does it stay in the "ON" or "OFF" position?

 

I realize this is an old thread but it came up from google when I was looking this up. My sons 1994 Toyota Pickup starting stuttering and stalling at a light about three weeks ago. I got it home and proceeded to search the internet for the symptoms and solutions. Over the last three weeks I have changed the plugs, plug wires, replaced all of the vacuum lines including the ones off the brake booster, changed the brake booster as it was rusty and questionable, PCV Valve and grommet, changed the IAC valve, & engine temp sensor. Today watching some video's and feeling like giving up I stumbled across someone saying it was their timing doing it. Ran to Harbor Freight and bought a $30 timing light, watched some how to videos and bam back on the road. With all the new parts she's running like a champ and pulling harder then ever. I just want to leave this here for someone else that might see it 7 years later and help. Don't be a dummy like me and do the timing first.