I have a 95 Sidekick I bought a few months ago. When it is started and driven when cold it bogs while accelerating from 2000-3000 rpm in any gear and when revved without load. It has done this always so I did a small tune up, new plugs gapped correct, NGK wires, Delco cap and rotor, PVC valve and fuel filter. I still does the same thing. After it is driven for 10 minutes or so and it warms up it runs ok, maybe slight power loss but very minor. This weekend I am going to tackle it again, check the TPS for sure. Any other things that can cause this? I might pull the intake apart and see how the MAF and TB look. I would like to dig into the EGR and clean that also. Any hints of things to check would be great.

Thanks,
Erik in Portland     

If it has a 3 wire O2 sensor (heated) you may have a bad heater
and it runs poorly until it heats enough to read the mixture and
send info to the computer

Wild

Any codes stored in the ECM?
This may help with the EGR, click on the links:
http://www.kick-fix.com/EGR-choice.html

no check engine light, i am gonna check for codes this weekend and check ox sensor and other things. thx for replies.

You know, it doesn't take 10 min for an O2 sensor to heat up, but it
can take an engine about that long to get to normal temp, you might
check the coolant temp sensor, not the gauge sender, the computer
sensor, if it reads wrong, like the engine is warm, it would be lean when
cold and run poorly

Wild

Hey Erik,
I think I tried to sell you my grey '94 kick a couple months ago. Anyhow I just changed my timing belt
And it made a big difference! Mine ran a lot like yours is running, I did the usual and changed everything
Without any help. The engine is a replacement with about 83k now, it was long over due! How many miles
does yours have on it? Ever been changed?

Kj

The 4 dr truck I bought has less than 60k on it. Pretty sure the timing belt has never been changed and that is due when it warms up a little more. I ordered all the stuff to do it yesterday! Last weekend I messed around more with it, checked all the plugs and gave it a good visual check. I checked the TPS, it checked out good on the adjustment. Oxy sensor is a 4 wire, has anyone tried the $20 universal ones on Ebay, alot cheaper than a direct fit version. Another thing I have noticed is if I baby it when I drive it seems to bog more and if I step on the gas more and keep the RPMs up it misses less. 

Thanks,
Erik in Portland

subscribed... i have the exact same issue.

Have you done anything to fix it?
I am going to check the coolant temp sender, install a new thermostat and look over things again this weekend.
Timing belt, h2o pump, compression check, valve adjust and O2 sensor in the near future. This will give me a chance to check/tighten the pulley and make sure the timing is correct.
Also thinking about throttle body and EGR cleaning and maybe injectors out to be cleaned and new seals. After that there isnt much left.
Almost forgot, need that full 2" exhaust with new cat, and a Kool Blue filter to get those hps/mpgs back the tires stole!
It runs pretty good now but would like to get it to REALLY good. 

Any help/recommendations greatly appreciated.

Thanks!
Erik in Portland

Got to check more things on the truck today. The ECT was ok hot and cold, ~4000 cold and 250 hot. I put in a new  correct thermostat, it had been changed at one point and had the oring AND gasket on there and always seeped a little. Pulled codes and only got the #12 and the CEL has never been on. Checked the timing, it was on at 5*, checked the MAF and IAT and all looked clean. Pulled the newish plugs and cap off and and everything looked fine. EGR moved easily and sprung back quickly. Whats left? Fuel side it seems. I would like to check the fuel pressure soon. Could be dirty injections? I ran a bottle of Chevron cleaner through recently and have a new fuel filter. Its about time to change the O2 sensor so that will probably happen soon. Any other ideas? Gotta drive it all week and see if anything seems different.

Thanks,
Erik in Portland

5 degrees with the jumper set?  I believe it should be around 8.

Funny you should say that.. it actually was at 8* but last night I remembered to check the factory sticker under the hood and it says 5* so I just moved it to 5* with the jumper, cant wait to see if it changes tomorrow morning when it is cold again.

Thanks!

Erik in Portland

It wasnt any better with the timing change and it seemed as though it was hesitating all the time now. Not just when cold. Any ideas?

You checked the ECT??? What's that?
coolant temp sensor?

The Engine Coolant Temperature Sensor:     ( ECT is the modern SAE name)
http://kick-fix.com/sensors/tests/ECT.html

kick fix is the best!

anymore ideas on my ill running rig? It is most noticeable from 2-3000 rpm and seems to be cold or hot now. I have a new oxygen sensor sitting beside me I will put in this weekend to see if that helps. I am out of ideas, I need to check the fuel pressure next and adjust valves next.

Confused,

Erik in Portland