So I've had my car for 2 years now and ever since i got it it has had a "load change" related bucking issue. Since ive replaced anything there is to replace (easily) i have learned that EGR should be 0 at idle or when in gear and TPS at 0%. I have thought about replacing the EGR valve and/or the IAC valve (beacause i thought it might be sticking). one day i plugged the EGR vacuum port and the condition lessened but was still there, and it ran way up into the red mark for coolant temp.. I thought if both need replacing, will it cause the car to miss and buck and jerk??? ---> If as soon as the throttle closes, the EGR is sticking open resulting in rich-or flooding the cylinder, or if when the throttle closes the IAC is sticking closed it will cause the same thing. If both are shot then will it be as bad as my car is right now???


Any input on this will be great.

Btw its a 92 Camaro Z28 Speed Density L98 5 speed manual.

 

What are the specs of the cam? (especially the LSA)

 

Is your car an original 350 car or did some replace the 305 with a 350. I ask because they didnt make a 5 speed 350 car from the factory. If there was a 350 swap, do you know if it was done correctly and does there appear to be anything missing on the engine.

 

You leave a lot of info out, so I'll "assume" that by bucking and jerking", that it happens when you're driving the car at speed...if so:

Disregard the IAC 100%...disregard the EGR, 99%

So while this bucking and jerking is happening, is the SES light coming on during the event?

 

Ill answer the questions in order here:
Cam: i have not the slightest idea, i did not do the swap but it might even be the origional 305 cam (i've heard of people doing this). Ill just say stock.

motor: originally a 305 swapped to 350, all displacement dependent sensors replaced (ie: knock, etc). No vacuum or electrical lines missing (aside from secondary fan switch which has nothing to do with this issue)

By bucking and jerking: yes i mean that it happens when i drive, sometimes when i come off of the throttle it will jerk into the jake brake mode like it will stall if it wasn't in motion. It does exeptionally well in the colder whether... No Check engine light aside from code 32 (EGR) which led me to think it was the valve sticking closed/open.

any ideas???


Thanks for the help guys.

 

Since you didnt do the engine swap yourself, kind of makes me wonder if the guy that did the swap also changed the prom in the ecm. The ecm should be the same for a 305 and 350, but the proms will be different. Do you know if he changed the prom? Might be something to check out.

 

oh i've been through a few proms, for now im running the stock 305 TPI manual prom and its been the best so far. TBI chips cant seem to get the damn thing right. I dont know if this is the cause though, a good point that it doesn't help the problem... we'll see.

 

305 Chip with 350 injectors. or 305 injector?

 

Supposedly the pervious owner who did the swap put new injectors in but who knows, i tried to check the serial numbers but i don't quite know how. it idles fine, and how can you expain the condition getting better with the EGR disconnected?

and thanks again guys.