Truck will start up but turns over a few times before firing up. 90 302. When it does fire it revs like the choke is on then drops rpms. And idle surges from little under 1k to nearly nothing almost dieing. With it in gear it does die. Once you get moving and warmer it stops doing it as bad but still hesitant takin off like a carb is loading up. Lastnight leaving a buddy's house it took about ten mins to start. Would pop like it tried then die. Peoples swearing it's my timing chain stretched out. Any ideas? Thank in advance

 

Have you checked for any codes? That's my 1st thought. Sorry I haven't looked to see about other previous posts you have had in the past. Last major tune-up? Another thought would be to trick the TPS. On the throttle body, use a thin and I mean Thin piece of cardboard, sorta as thin as your oil filter comes in, and stick it betwen the Throttle stop screw and the throttle lever. If you get it started, and the idle may be high, but it will be running, get the timing light on there and check your base timing. With the SPOUT out, see if your @ 10BTDC and whether or not it's jumping around. This may also be evident even with the SPOUT in, since if the chain is really stretched out, your timing is gonna be 16 then 14. Also, see if the crank dampener hasn't slipped on the outer the ring.

Start with codes, and let us know what all you find out.

 

i attempted to pull the codes KOEO i got 51,34,15,13 not sure how accurate they are as this is the first time iv pulled codes on a obd1.

 

If you think its a bad timing chain , check the slack in it , just pull off the distributor cap off and turn the crank buy hand till the rotor moves , then turn it back the other way to see how far you turn it to get the rotor to move , if its more than 5 deg i would replace the chain and gears....Lew

 

Thanks lew..I really have no idea what it is. Alot of people have told me timing chain. Does that sound right?

 

X2 what Lew52 suggested! I had forgot about that method.

Code 51: You have an ECT (Engine coolant temp) sensor problem. ECT sensor out of range/circuit open.

Code 34: Defective EGR pressure transducer sensor.
Code 34: EVAP control system fault/voltage higher than closed limit.
Code 15: EEC (PCM) Read only memory (ROM) test failed
Code 13: RPM at idle out of range/low

 

There are alot of things that can be the problem , if the chain jumped a tooth it is one of them , let us know what you find....

 

I know why I have code 51 my temp gauge wasn't working and I had a mechanical one Layin around so it's on a pillar now. EGR where is that sensor located? And when bad what does that effect? It's just confusing cuase after I drive it a few mins it stops trying to die but the idel is still a tad rough.

 

The computer uses a different sensor than the dash gauge. The ECT should be located on the thermostat housing. Its easily checked with a ohm meter. Fix that problem first before dealing with the other codes
regards
rikard.

 

There's nothing on the thermo housing that I seen today. I replaced my thero but I'll double check.

 

Yeah, the ECT is near the thermostat housing. Should be located on a pipe that extends out of the manifold. On that pipe, there should be hoses that connect to the throttle body and another one for the bypass of the water pump for the heater core.

 

You can get a coolant temperature sensor code if the truck is not at operating temperature even though the sensor is still o.k. Keep that in mind as you troubleshoot the codes.

 

I have a mechanical temp gauge now. The one kn the gauge cluster is no longer in use does that effect any thing

 

iv read some where about cross flow between the tanks..will that effect the way it idles and all? i went a total of mayby 10 miles today and burned a 1/4 tank..its eatin fuel bad now..this all started happening after one night my buddy said his ranger would beat my 5.0 so we raced a bit and now im dealin with a truck thats eating fuel and not running right...